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360 Blog, Bill Zimmer: Best subject line ever

Best subject line ever

Email marketers are fanatical about subject lines. And for good reason—if you can’t get people to open your email, all the work you put into your campaign feels wasted. In fact, 1 in 3 people decide whether or not to open your email based on the subject line alone. Yikes.


Here are some tips to improve your email open rates.


The folks at Digital Marketer keep a running list of the year’s best subject lines, as well as a great list of 8 elements you should consider when writing yours:


  1. Self-interest—Be direct and play to their ego. Highlight a personal benefit.
  2. Curiosity—It’s okay to be a little vague. Make sure to pay it off when they open your email though. Otherwise, click-through rates won’t be that great
  3. Offer—Give the reader something awesome. People do a lot for free stuff.
  4. Urgency/Scarcity—Nothing encourages an open more than a hard deadline.
  5. Humanity—Don’t always try for a hard sale.
  6. News—Keep your readers a step ahead and they’ll stay interested in your emails.
  7. Social Proof—Case studies, testimonials, or third-parties can lend credibility to whatever you’re pitching.
  8. Story—We’re social animals who love telling stories. Start one in the subject line and carry it through to your email.


That’s a lot of good ideas. But how do you know which subject line will perform best?


Trick question. You never will. Your audience’s motivations change day to day, hour to hour. Plus, you can’t just resend the same thing that worked last time. But don’t worry—there is one way to help predict which subject lines work better than others for your audience.




The worst thing you could do is to send an email blast with one subject line to the whole group. Why? Because you can’t evaluate its effectiveness. Maybe the weather messed up people’s commutes. Maybe there was a big sports championship that distracted your audience. Maybe it was just another manic Monday after a Sunday Funday.


The only way to evaluate your subject line performance is to A/B test the heck out of your email lists.


For example, say you test a “News” subject line vs. a “Social Proof” subject line. And you see that the “News” subject line performed 10% better. Next time, try another “News” subject line as the control, and test it against a “Story” subject line. Write, measure, repeat.


When you test and evaluate your email marketing religiously, you’ll accumulate valuable evidence of what elicits a response from your audience. Moving forward, you can use this data to inform your next email subject line test.