The Best Tips on Writing Email Subject Lines That Work

There's no point sending out an email with a subject line that doesn't grab attention, speak to the readers, and compel them to open and read the rest of your email. Yet the subject line is all too often an afterthought -- written in just a few seconds, after the body of the email has already been finished. Much like a headline on the front page of a newspaper, an email subject line is your best chance to attract the reader, and it can make -- or break -- your email campaign.

Let's explore what makes for a successful subject line.

Aweber, an email marketing company that has studied millions of subject lines, lists its most effective subject line to date as, quite simply: You Are Not Alone.

Why does this subject line work so well? It's all about the "need to belong," according to Sean Platt in a post on Copyblogger:

"I've seen this subject line used successfully on emails ranging from content marketing to personal development to potty training, with a dozen verticals in between. The results are always the same. I don't want to be alone is a compelling, universally recognized statement. The need to belong, to know that others are going through the same life experiences, is primal."

Besides using "You are not alone" as the subject line in your next email marketing campaign, here are some tips to help you create a strong subject line that boosts your open rate.

Be Relevant: What’s a hot button for your readers? You need to know what’s going on in their world to grab their attention. Try incorporating a relevant and timely item in your subject line.

Be Clear: Don't get too clever with your subject lines. Be clear, and tell the reader what to actually expect in the email. An article from MailChimp sums this up nicely: "Don't sell what's inside. Tell what's inside."

By the Numbers: Including a number in your subject line can make it seem like the content won't ramble on forever. “4 Ideas for Improving Sales Today,” for instance, makes me think, “OK, I have the time to look at four ideas and maybe get a good one or two.”

Active Is Better Than Passive: Subject lines that lead the reader further into the email, that suggest action, are better than subject lines that go nowhere. Have the subject take the reader by the hand into the text. Be active.

Word Count Counts: Conventional wisdom tells us that a subject line that works is only 5-8 words and 40 characters long. Think of passing a billboard at 60 mph, or a bus with a banner on the side passing you on a crowded street. Similarly, Microsoft Outlook, Mac Mail and just about all email applications display only the first few words on a subject line, so make sure yours is short and sweet.

Test and Test and Test:  A/B split testing doesn't have to be overly complicated. Just try the following: If you want to see what subject line is getting the best results, write two. Take 25% of your mailing list, split that in half, and send one subject line to Group A and another to Group B. Wait a few days and then look at the open and click-thru rates to see which performed better. Use the subject line that performed better for the remaining 75% of your mailing list.

For inspiration, check out some of the best and worst email subject lines from a comprehensive study by MailChimp of over 200 million emails.

What other email tips have worked for you?

Guest Author:  David Grebow is a freelance small business journalist who writes for Vistaprint, a leader in custom websites and other marketing products and services for micro businesses all over the world. David holds an MBA from Harvard, and has written for Harvard Business Review and The Economist.