Let’s talk about something that’s been on my mind: email marketing tests. Not just the “throw spaghetti at the wall and see what sticks” kind of testing, but actual, meaningful experiments that help you improve performance.
I see a lot of people either over-test—changing things so often that they never learn anything—or under-test, sticking with the same strategies even when they could be doing better. Testing in email marketing isn’t about busywork. It’s about running experiments that give you real, actionable insights.
My First Marketing Job and the Power of Testing
My first marketing job was supporting major IT companies and resellers through email nurture campaigns and custom landing pages. At first, we were just told to get the resellers on the program, collect their email lists, and send out pre-made email templates and landing pages. It was a rinse-and-repeat process.
However, a few months into the role, I was shocked at how poor the results were. Open rates were hovering around 10%, click-through rates barely hit 1%, and conversion rates were even lower. We were generating pipeline revenue, but it wasn’t nearly as much as expected. Something wasn’t adding up.
That’s when I decided to take matters into my own hands and start running tests. I experimented with subject lines, CTA placements, offer positioning, and segmentation strategies. Within the first quarter of testing, open rates increased by 40%, click-through rates doubled, and overall engagement significantly improved. More importantly, these changes contributed to an additional $3.2 million in pipeline revenue over the next year.
Not only did I boost the performance of our campaigns, but this approach ended up reshaping how we operated. Over time, we shifted from just being executioners of pre-made templates to actual advisors for these companies. More teams internally started adopting this testing-first mindset, and the company as a whole became a more valuable service provider.
That experience shaped how I think about email marketing to this day. Testing is critical, but it has to be strategic. I used to think every email needed a test, that we always had to be tweaking and optimizing. But over time, I learned that not every send is worth testing—sometimes, you need to step back and focus on the big picture.
When to Test (And When Not to)
You don’t need to test everything all the time. The old advice of testing with every send? Forget it. That’s just noise. A good rule of thumb is about one test per month. This way, you can actually implement what you learn without constantly changing things up.
And don’t forget about automated emails. If you’ve got welcome sequences, cart abandonment emails, or lead nurture flows running, test those too. These tend to have higher engagement, so the insights you get from them can be even more valuable than batch-and-blast campaigns.
What to Test: The Good Stuff
These are the tests that have consistently made an impact for me:
1. Subject Lines
The first battle in email marketing is getting people to open the email.
B2C examples:
- Urgency: “Last chance!” vs. “24 hours left!”
- Curiosity: “You’ll never guess what’s inside…”
- Personalization: “Kyle, this is for you”
- Offer Placement: “20% off today only” vs. “Exclusive deal inside: 20% off”
- Tone and Style: Playful vs. direct
B2B examples:
- Urgency: “Your Q2 strategy needs this today” vs. “Final hours to optimize your pipeline”
- Curiosity: “The B2B trend no one is talking about”
- Personalization: “Kyle, streamline your sales process now”
- Offer Placement: “Exclusive report: 2024 B2B growth trends” vs. “Unlock insights for better lead conversion”
- Tone and Style: Professional vs. conversational (e.g., “Let’s talk ROI” vs. “Your marketing ROI is suffering—here’s why”)
If you have an offer, then put it in the subject line. Every time. Don’t bury it.
2. Call-to-Action (CTA) Buttons
Your CTA needs to match where the reader is in their buying journey. Test:
- Copy: “Shop Now” vs. “Start Browsing”
- Length: Two words vs. five words
- Personalization: “Kyle, claim your discount”
- Number of CTAs: One clear ask vs. multiple options
Clarity almost always beats cleverness—except for that one client of mine who proved otherwise. Always test to be sure.
3. Offers and Discounts
More isn’t always better. Some brands have found that 15% off performs just as well as 25% off. That’s free money back in your pocket. Also, test whether you even need a discount. Maybe just reminding people about your product is enough to drive sales.
4. Email Frequency
Are you sending too often? Not enough? The only way to know is to test. Try sending fewer emails to a portion of your list and see if revenue holds steady. If it does, congrats—you just saved yourself from unnecessary unsubscribes.
5. Send Time and Day
Everyone’s inbox is a battlefield. If you’re in e-commerce, Monday mornings might work. If you’re a restaurant, Friday afternoons might be better. Test it. And don’t just test “what’s the best day.” Test whether sending multiple emails over a promotional period beats one and done.
6. Personalization Beyond First Name
We already know adding a first name works, but what about deeper personalization? One of my favorite tests involved using past behavior: “Fly back to Denver with this special offer!” instead of a generic subject line. That kind of tailored messaging can be a game-changer.
7. Long vs. Short Emails
Length doesn’t matter unless your email is getting clipped by Gmail. But test whether concise copy works better than storytelling for your audience. If your emails are skimmable, you’re on the right track.
8. From Name and Email Address
A B2B email might get more responses if it’s from “Anna at ClearWave Fiber” rather than just “ClearWave Fiber.” People like talking to people, not faceless brands. Try it and see.
9. Video and Images
Video usually increases engagement—but not always. A bad video can actually hurt performance. If you’re using video, make sure the thumbnail clearly shows what it’s about. Also, test static images vs. GIFs. Movement can catch attention, but it can also distract.
10. Automation Timing
This is a big one. The first email in a nurture sequence should always go out immediately. But what about the follow-ups? Test the spacing: One day later, three days later, or a week later. The right timing can make all the difference in keeping people engaged.
Determining a Winner
Don’t just eyeball your test results. Use a statistical significance calculator (SurveyMonkey has a free one). This ensures that your “winner” is actually a winner and not just a fluke.
And if you’re not sure where to start? Look at your top-performing emails from the last year. Find common themes, and start testing variations of those.
Final Thoughts
AI has been mainstream for over two years now, yet I still see marketers struggling to make the most of it. AI can help with brainstorming subject lines, predicting optimal send times, and even generating personalized content variations. Use it as a tool—not as a crutch—to speed up testing and get better results.
Testing isn’t about proving you’re right. It’s about finding what actually works. Run meaningful tests, document your findings, and refine as you go. You’ll get smarter, faster, and more effective with every email you send.
Now, go have fun testing something.
