improve email open rates

5 Easy Hacks to Improve Email Open Rates

Few digital marketing arenas are as competitive as email—that’s why it’s so important to learn how to write subject lines that improve email open rates. 

To help you on your way, we wrote this article (and this one too) to help your brand’s emails POP amidst all the inbox clutter generated by angry bosses, doting mothers, Nigerian princes, and all the competitors in your industry. 

Start asking questions

At Zeta, we’ve seen a clear pattern where subject lines framed as questions outperform subject lines framed as statements.

Hey Jackie, did you hear the news?


Hey Jackie, check out our latest product!

The best questions to ask are those that…

  1. Open a dialog with the recipient.

  2. Your email content will answer for the recipient.

  3. Trigger an emotional reaction from your recipient.

Questions are a psychological tripwire. When people see a question, they feel compelled to discover the answer or offer a reply. More importantly, asking questions increases your message’s (and therefore your brand’s) likability in the eyes of recipients

Here are some examples:

Make use of numbers and lists

Lists and numbered lists are still a great, eye-catching way to snag attention in a crowded email inboxes.

For whatever reason, people’s eyes are naturally drawn to numbers and lists (at least that’s what science says). Therefore, you should try to incorporate “listy” elements into your subject lines. 

Things like…

  • Top 10 Vacation Destinations for 2021

  • 5 Fall Fashion Tips No 20-Something Should Ignore

  • The 3 Best Credit Cards for Cash Back Rewards

Are always going to see more opens than subject lines that look like…

  • Great Vacation Destinations

  • Cute Fall Fashion Ideas for 20-Somethings

  • Top Credit Cards for Cash Back Rewards

Be a tease

There’s something compelling about a little mystery, which is why “teaser” subject lines can be so effective at driving up open rates.

Having said that, delivering “the goods” with your email—while always important—becomes imperative when using a teaser subject line. The last thing you or your brand want to do is leave people feeling unsatisfied. So, whatever teaser you use, you MUST make sure the substance of your email is going to back up the enticement of your subject line.     

Put another way, you need to reward the curiosity that drove your recipient to click “open.”

Some examples…

  • It’s All Ends April 19th

  • Will You Support Us?…

  • We Weren’t Going to Say Anything…

  • You Told Us What You Wanted to See…

  • This Is Why We Can’t Have Nice Things…

Use shock and awe

Blunt, matter-of-fact, and shock-and-awe subject lines that cut to the chase get a lot of opens—especially if they’re targeted to the right audience.

  • Help Me Defeat Donald Trump This November!

  • Don’t Let Nancy Pelosi Destroy This Country!

  • People Are Going Broke!

  • We’re Going to Lose $$$ On This Sale!

  • Never Write Another Job Application Again!

The final tip if you want to improve email open rates?—TEST! 

The only way to truly know what’s working and what isn’t in your quest to improve email open rates is to test. 

No, not just test…but test aggressively

The previous four hacks are good starting points to improving your open rates, but none of them are magic bullets. There’s no way to know with 100% certainty what combination of words will drive them most opens from your unique email audience without testing. 

Testing (coupled with optimization) is the ultimate open-rate-improving hack, so always benchmark your best performing subject lines against your new ideas. 


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