Advanced Email Marketing Strategies for 2025: Marina Caroll on Running High-ROI Campaigns

Many DTC brands are still stuck in batch-and-blast territory, defaulting to fixed schedules, flat messaging, and outdated testing practices. But if you're aiming for sustainable retention and higher ROI in 2025, that mindset just won’t cut it.

Marina Carroll is the Head of CRM Strategy at New Standard, a retention marketing agency for DTC brands like AG1 and True Classic. She has helped dozens of DTC brands like BYLT and Caraway rethink their email strategy. Her approach? Ruthlessly goal-oriented execution, with a clear revenue target in mind and every lever focused on hitting it, whether that’s email, SMS, push, or onsite.

We spoke with Carroll to unpack strategies that drive conversions for email in 2025, what founders and retention marketers are still getting wrong, and how to set up your email program to consistently hit goals.

Our interview with Marina Carroll on advanced email strategies

Q: What does a high-performing email marketing strategy look like in 2025?

The most important thing is having a goal. What are we trying to hit? Monthly revenue? Campaign performance? 

Once we define that, we decide which levers to pull to get there. That could mean an extra send on a campaign day, an SMS send before quiet hours, or broadening flow triggers to increase delivery volume. 

It’s no longer about "this is what we always do," it’s about being flexible, tactical, and focused on outcomes.

Too many brands still think they’re doing email marketing because they’re sending something. But they aren’t squeezing out every dollar from the tools they have. If you only have one abandoned cart email, and it’s working, why stop there? Add more until it plateaus. Maximize the ROI of every channel.

Q: What channels do you consider part of retention now?

Email is still the core channel for most brands, but SMS and push are just as important when used well. We also support brands on popup strategy and website conversion.

So the major revenue-driving levers are: email, SMS, push, and onsite capture or optimization.

Q: How do you see email working in tandem with other channels?

Email still makes up the majority of retention revenue, but SMS is catching up. Some of my clients are now seeing 50/50 revenue splits. 

It’s about building the SMS list with intention. Add SMS sign-up prompts to your email footer, run giveaways, place QR codes in-store—build it like a real channel. 

Push is still underutilized, but it’s basically free and can drive strong incremental revenue if used right.

Q: How do you use the three channels together to build on each other and drive stronger results overall?

Email is your business-as-usual, everyday revenue driver. It’s your core channel. So you don’t want to overdo it, but you do want to meet people at the right moment based on behavior.

I use SMS when I want to drive a revenue spike, showcase something new (like a fresh product shoot), or promote loyalty and membership benefits. It’s not for sending daily reminders to buy your bestselling tee. People want value, exclusivity, or newness in that channel. This is similar for push notifications—sharing for exclusive content you're not going to see every day, like with a basic email.

Every sale campaign uses all three channels, but we time them separately. You want to hit them at different points of the day, make them different touchpoints, so at the end of the day, they see it 7 times to finally get that purchase.

The way we approached it with a apparel company recently for a Memorial Day sale is that they [their shoppers] get a launch SMS, launch email, a follow-up SMS later on letting them know that styles and sizes are going quickly, and then they also get a push notification at a different time that says that if they’re a VIP member, you exclusively get 15% cashback. 

Then, for people who aren't VIP members, they get another push that says you can get 15% off if you sign up for membership programs.

It seems like overkill in messaging, but it's also the second biggest sale of the year. So, you actually kind of have to do a little bit more messaging during these time periods to break through the noise.

Q: How long are you waiting between each message?

I don't think there's an exact science, but I always send out messages between an hour or two hours.

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We would shoot out a start email for VIPs early in the morning (around 6 or 7 am). Then you have quiet hours for SMS, so that message goes out at around 10 am because you can't shoot that any earlier. 

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For push notification, I always send it around lunchtime as a separate touchpoint. There’s another SMS in the PM hours between 4 and 5 pm, which seems to do really well for this brand specifically. 

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Then sometimes we'll do a late-night email too, right around 7 or 8 pm to hit them while they're in bed scrolling through their inboxes. 

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Q: How do you typically approach the content mix in email marketing for ecommerce brands?

I use a simple rule for most brands: 80% of your emails should drive revenue, 10% should focus on brand moments, and 10% is open for creative or timely campaigns. The 80% should be merchandised, tested, and optimized. 

The 10% brand content helps humanize your brand. Think sustainability updates, influencer events, things that build loyalty even if they don’t convert. The last 10% is for flexible content like holiday campaigns, back-in-stock alerts, or anything timely.

Q: Do you ever blend those buckets into a single email?

It depends on the brand. If they’re okay with a blended approach, I always include merchandising, even in brand emails. 

For example, a sustainability update email might end with a soft CTA to explore products aligned with that mission. It keeps revenue in the mix without diluting the message. 

But if the brand wants to go fully brand-first for a moment, that’s okay too. One send won’t tank your numbers. You test and you adapt.

Q: When it comes to testing, what actually moves the needle?

Most people default to subject lines or button colors, but those don’t usually drive significant impact. Our testing roadmap focuses on strategy-led questions. We test pricing models (percentage vs. dollar-off), short vs. long copy, single products vs. sets, and low entry point vs. high AOV.

Start with a hypothesis. Don’t test randomly. If you test a subject line, make sure it teaches you something you can scale, not just "which word gets more opens." And always measure outcomes in terms of revenue per email (RPE). That’s what we optimize for.

Q: What are your thoughts on segmentation and personalization?

Hyper-segmentation often backfires. For big DTC brands, broad sends to engaged segments almost always outperform ultra-targeted flows. If you have a cookware brand and you only email people who bought a pan about a lid, that’s a missed opportunity. 

A broader campaign to your engaged 30-day or 90-day list will likely drive more revenue, with the same design and copy effort.

Use platforms like Klaviyo to build test segments and compare performance. If a general engaged segment outperforms your hyper-personalized version, stop overthinking it.

Q: So, when does personalization work?

Personalization works best within your segmentation strategy, especially when it coincides with your messaging or the actual copy within your campaign. We’ve seen solid results from light personalization, especially in post-purchase flows, and we’re talking to you as if you’re a new/recent customer. 

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Another tactic that we find works for personalization is talking through the next purchase (this is mostly for first purchasers). If someone buys a t-shirt and the next most commonly purchased product is pants, we’ll show them pants next. That journey, based on data around top product pairings, always performs well.

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What doesn’t work is splitting flows across every product. If you’ve got 10 best sellers and try to build 10 personalized journeys, the return on investment breaks off after the second product. So, testing slowly instead of overbuilding is the way that we find successful with most of our brands.

Q: How do you use RPE in reporting?

Revenue per email (RPE) is simple: revenue from a campaign divided by the number of recipients. It’s one of the best directional metrics to understand performance over time. 

If we change a flow and the RPE goes from $1 to $1.15, we know that’s scalable. Apply that lift to the whole year’s send volume, and you can see the impact.

Q: How do you identify changes that will lift RPE sustainably across larger sends?

RPE is a tricky one because it does vary vastly when you increase or decrease segment size. So the way we analyze that is through sets of averages, and we also apply thresholds. 

So, if we usually sent to around 400,000 people, but an email with a survey only went out to 2,000, that’s an outlier.  It wouldn’t be included in our core analysis because it can inflate or deflate RPE in a way that doesn’t reflect reality.

Knowing your thresholds for your data to analyze RPE properly is important, and then segmentation is how that’s going to be improved. So, click-based or engaged segmentation instead of big bucketed segmentation, where you're going to get more dollars, but your KPIs are going to tank. 

But, if you're looking for a super targeted RPE, it's going to be tighter segmentation (even click-based) and then also inclusions of people either abandoning or viewing certain products that you're pushing in those emails in the last x amount of days.

Q: What role is AI playing in your workflow right now?

Personally, I use AI heavily for copywriting and reporting. I don’t use copywriters anymore for 60+ campaign emails a week. I create GPTs trained on the brand’s tone and use them to generate strong first drafts. It’s massively reduced time-to-send.

On the reporting side, I paste data into ChatGPT and ask for patterns or takeaways. It helps validate my instincts and adds clarity for my team. 

For the brands themselves, AI in tools like Attentive is still in beta. Sometimes it works, sometimes it sends something off-brand. But I believe AI is a massive unlock for anyone who learns to use it with care.

Q: What advice would you give a brand that wants to improve its email program?

If you're working with an agency, trust their process. Let them run. Ask for reporting and clarity, but don’t micromanage the strategy. 

If you're running things in-house, audit your flows. Most brands I work with are missing core flows like browse or cart abandonment. 

Make sure your flows are firing, properly triggered, and updated. That’s 75% of your attributed revenue right there. Then pull more people into those flows, increase delivery intelligently, and optimize from there.

Q: How long after cart abandonment should the first email trigger?

Whenever we do the analysis on this, we look at the brand's time to purchase between sign-up and first purchase. It also depends on your periods. 

For sale periods, I'd say 15 minutes. Non-sale periods could be 4 hours. 

Faster-moving, cheaper product companies that have a lower AOV (like $35 to $40) would be maybe 45 minutes. Products that are $700+ need more time to think on and are a bigger purchase, 4 hours. 

There are many different factors we look at when setting the time triggers, and always, at the end of the day, testing is key. 

But in general, taking all of the products and AOVs out of it, shorter is better, for the first send, at least. I’d recommend a couple of hours to 30 minutes. And then always testing after that.

Q: How many emails should be sent, and when do you see revenue drop off?

I'd say in general (based on what we see with brands), about three emails is right. 

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I always check the placed order rate. So if the placed order rate is still carrying well, I will add another email and test it. I delay it by a couple of days to let people sit on it and see if it converts. If it’s anywhere around 0.2, 0.3, or 0.4%, I’d say that’s probably not driving necessary revenue. It’s not worth it, and you’re probably making more people angry than you are helping. 

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But an analysis is always done before you decide to turn off an email that seems to be underperforming.

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A “placed order rate” measures how many people who receive a message actually place an order within a specified timeframe. It's calculated by dividing the number of unique orders placed within the attribution window by the number of unique recipients of the message.

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Q: When do you start adding discounts to those cart abandonment emails?

This is brand-by-brand specific. Some brands never give a discount if a shopper has abandoned their cart, and some brands offer one right from the first email. It really just depends on the goals of the brand. 

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Some brands don’t care about 15% or 20%—they’re just here for the conversion. And some clients are like, “I won’t even give 5% because I need to keep the integrity of my brand upheld through the course of the series.”

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In general, I would not personally introduce a discount until email three. You have a good chunk of people that are just converting from the first and second email reminders. And so after that, email number 3 is where I would suggest it. 

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But again, it should always be tested. The problem with testing this is, when you bring it into your 2nd email, it’s going to outperform. When you bring it in at number one, it’s going to outperform. So you have to run a margin analysis to say, “How much more did I keep in my pocket by not offering it here? But how many more people did I convert?” 

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Do a comparison to see if the discount is worth your margin, and then deploy your other strategies from there.

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Q: Should they highlight the actual product the shopper viewed? Any other personalization tricks?

Resurfacing the product that the person abandoned has always tested out as more revenue-driving than not. 

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But I also think that switching it up (some of our clients have four abandoned cart emails) in the third one, not showing the product, and doing more of a hero image with why our brand is amazing or the unique qualities of the brand. That has always seemed to work well, too, just to shift the visual.

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Q: How do you know when a flow has hit saturation or isn’t improving with more sends?

It depends on what you’re looking at, but again, I use placed order metric. So if it starts to dip below 1% on that visual within Klaviyo, it’s showing to me that the message isn’t resonating strongly enough to keep sending emails. They’ll either convert on their own, or we wait a week and then try again. That’s how I measure placed order.

TL;DR: Marina Carroll’s advice for better email marketing in 2025

Strategy: Multi-channel approach prioritizing revenue goals

• Anchor every retention decision to a clear goal, whether it’s monthly revenue or campaign-specific performance.
• Think beyond just sending emails. Your strategy should unify email, SMS, push, and onsite to work toward that north star.
• Use SMS and push notifications intentionally, not for daily reminders, but for moments of urgency, exclusivity, or newness (e.g., product drops, VIP perks).
• Orchestrate touchpoints across the day to avoid fatigue and maximize exposure (e.g., email in the morning, SMS mid-day, push later)
• Every major campaign should use all three channels, staggered in timing and varied in message format, to create multiple touchpoints.

Execution: Build for consistency, not campaigns

• Use the 80/10/10 rule: 
  
  • 80% of campaigns should focus on driving revenue
  • 10% on brand-building
  • 10% on timely and creative campaigns.
• Don’t over-personalize. Broad sends to engaged segments often outperform hyper-targeted flows.
• Blend brand and sales messaging when needed, but always include a path to purchase.
• Use discounting strategically (generally not before the 3rd email reminder) and always compare lift vs. margin loss in A/B tests.

Optimization: Test for revenue, not novelty

• Instead of superficial tests like button colors, test elements that drive real results like pricing models, copy length, AOV entry points, and product bundles.
• Always start with a hypothesis and measure success through RPE (Revenue Per Email), not clicks or opens.
• Scale what works. If a flow sees even just a $0.15 lift in RPE, that lift compounds at scale.
• Use threshold-based analysis to avoid skewed RPE data. Remove outlier sends and segment based on actual engagement (clicks, views, add to carts), not inflated open data.

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Flow management: Refine every detail

Timing

• Set the first email to trigger between 30 minutes to 2 hours after abandonment.
  
  • For lower AOV products, aim for 30-45 minutes.
  • For high-consideration products (e.g., $700+), wait up to 4 hours.
  • During sale periods, move faster. 15 minutes can be the sweet spot.
• Always test timing against your brand’s time-to-purchase data. There’s no one-size-fits-all.

Frequency

• Most brands see the best performance with 3 reminders in the flow.
• Evaluate your placed order rate to decide if a 4th email is worth it. If the rate drops below 0.3–0.4%, it’s likely not driving enough incremental revenue. Below 1% is usually your threshold for pausing or restructuring that email.

Product surfacing

• Always resurface the exact product they viewed in at least the first or second emails. This consistently drives more revenue.
• In later emails (3rd or 4th), consider shifting to brand-led visuals or hero storytelling to re-engage without being repetitive.

Discounting

• Wait until the 3rd email reminder to introduce any offer, if at all. Many brands convert without discounting in the first 2 sends.
• When testing discounts, conduct margin analysis. Did you drive enough conversions to offset the revenue lost to the offer?

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Use AI for speed, not shortcuts

• Use GPT-powered tools to generate first drafts, freeing up time to focus on strategy.
• Leverage AI for reporting pattern recognition, but apply human judgment before acting.
• Stay cautious with in-platform AI (like Attentive’s), which may still require brand training.

Set your ecommerce brand up for better email conversions!

Marina Carroll’s insights make one thing clear: email marketing in 2025 is no longer about doing more, it’s about doing it smarter. From goal-led campaign strategy to AI-powered copy, brands that prioritize performance over perfection will see the biggest wins.

But none of that works if your emails aren’t landing in your shoppers’ inboxes. Email deliverability is the foundation of any high-performing email strategy. It's also one of the biggest challenges for brands, causing them to miss out on revenue opportunities. 

That’s where Tie can help. By improving inbox placement, reducing bounce rates, and ensuring that your core flows reach the right people at the right time, Tie gives your email marketing efforts the infrastructure it needs to target and convert shoppers effectively.

Book a demo to see how Tie can improve your email deliverability and increase conversions.