10 techniques for writing significantly better email subject lines
Do your email subject lines matter? Absolutely — and maybe more than you think. It’s not just about getting higher open rates. Every time a subscriber opts not to open one of your emails, you’re missing an opportunity to connect with them and strengthen that relationship.
And of course, your list members are less likely to take the action you want, like making a purchase, if they don’t open your emails. Plus, over time, you’re training your customers to ignore your messages, which can unleash a cascade of problems.
With so much hinging on a simple subject line, you’ll want to do everything in your power to make your subject lines as strong as possible. Before you send your next email, take a few minutes and use one or more techniques from this list.
1. Highlight the discount
Are you sending out an email with a discount code in it? Then don’t worry about being clever or coy. Be as straightforward as you possibly can. Is “Get 10% off your next purchase” a boring subject line? Yep. But that’s a good thing.
As host Kurt Elster said in a discussion of subject lines for emails with discounts on The Unofficial Shopify Podcast, “The more clever I become with the subject lines, the poorer they perform. You want to be really direct.”
2. Do a specificity sweep
Joanna Wiebe of Copy Hackers has a useful technique that you can use for email subject lines: the specificity sweep. In this video, she walks you through the process of applying it to an entire email. But it’s also a fast and effective (but not easy) technique you can apply to subject lines.
In a nutshell, review your copy and ask yourself if it’s annoyingly broad: “Check out our new spring arrivals.” It’s not going to upset anyone — but are people really going to be inspired to click? Specificity can feel a little risky. But if you want people to open your emails, review your subject lines and look for ways to be more specific.
3. Get inspired by 164 examples
We’re fans of OptinMonster here — it’s one of the great third-party email acquisition tools that you can integrate with your Klaviyo account. And if you’re looking for inspiration, you’re going to love their list of 164 of the best email subject lines out there.
From FOMO to humor to straightforward subject lines, these examples — from retailers, SaaS companies, and famous folks — will jumpstart your imagination.
4. Follow a headline formula
If you’re more process-oriented, dig in and discover how a winning email subject line is crafted. The lengthy list of headline formulas from Sumo gives you tons of options to choose from, ready for you to personalize and make your own.
For example, according to the list, you can use the formula “[Insert Celebrity] School Of [Topic]” to write subject lines like “Bruce Lee’s School Of Self Defense,” or “Stop [Action]!” to write “Stop reading the news!” It’s a great way to go beyond your usual subject lines and start thinking differently.
5. End with a question mark
Should you always end a subject line with a question mark? Of course not? That would be excessive? But when we were putting together our Fashion Ecommerce Benchmark Report (get your free copy!) with our friends at Yotpo, we learned that there are times when it’s a good rule of thumb.
Yotpo analyzed 3.5 million emails that retailers sent to ask customers for reviews. Turns out that the punctuation mark at the end of an email subject line made a difference. Ending with an exclamation point? Expect a 27% decrease in review conversions. Ending with a question mark? You could see a 23% increase.
6. Write 25 subject lines
How many possible subject lines do you write before you choose the one you’ll use? One? Maybe two or three? Take a note from the famous Upworthy practice of writing 25 headlines for every article (find out what that’s like to actually do). Draft 25 possible subject lines for your next email campaign before you settle on a winner.
If it sounds excessive, give it a try anyway. As anyone who’s ever tackled the popular “40 uses for a brick” creative writing exercise can tell you, your creativity really does kick in. You can end up with some surprisingly good ideas.
7. A/B test with purpose
We can’t say enough good things about the value of A/B testing all kinds of elements in your emails, including subject lines. If you want to A/B test your two favorite headlines, that’s a solid use case. But it’s even better to A/B test with purpose. That’s a good way to turn up durable insights that you can bring with you into future headline experiments.
ConversionXL wrote a comprehensive 6,000-word guide to A/B testing. In it, they explain how to plan your site-wide A/B testing around clear hypotheses and priorities. You can snag their prioritization framework and adapt it for email testing. Consider choosing variables like personalization, capitalization, and more.
8. Go to your own inbox
As marketers, sometimes we forget about the human impulses that get people to open an email. Even classics like “what’s in it for me?” can get forgotten after too many hours of staring at a screen.
Refresh your memory by going to your own email inbox. Look at which promotional emails you’ve actually clicked on. (Hint: If you’ve unsubscribed from all of your mailing lists, this is a good time to subscribe again.) Using this technique, I’ve noticed that while cryptic headlines are fun to write, I’m not as likely to open those. However, I’ll open emails when the subject lines make me laugh or announce a product launch or update.
9. Hey — be skeptical, okay?
To improve your email subject lines, bring a healthy dose of skepticism to tales of record-breaking examples. Yesware explains why in this cautionary tale about using the word “hey.” Yes, it brought in record-breaking results as the subject line of a famous political fundraising email. But it also dragged down open rates in half a million sales emails.
You’re better off revisiting your own successes and scrutinizing open rates. See what’s worked in the past and look at how you can leverage it for future emails.
10. Improve your preview text
Sometimes the subject line is just about perfect, but it needs some extra oomph. Follow up with great preview text. As Klaviyo’s Phil Weltman points out, you can probably do a lot better than the frequently spotted “Having trouble viewing this email? Click here to view it in a web browser.”
Ideally, your preview line should complement your subject line, like any other classic pairing, he ads. “Your preheader text should be the peanut butter to your subject line’s jelly — used in unison with your subject line to entice your reader to open the email.”
And if you still can’t find the perfect subject line…
…it might be because you need more than one. If you can’t figure out how to make that subject line work for everyone on your list, it could be for a good reason. Your list is probably made up of two or more distinct groups.
Instead of searching for the perfect one-size-fits-all headline, divide and conquer. Break your list down into segments (just like a targeted email marketing expert would) and send out emails to different segments with subject lines tailored especially to them.