Email Subject Line Dos & Don’ts

As marketers, we all strive for that coveted email open, but we also know how elusive it can be. With the average person receiving almost 100 business emails a day, how do you write a subject line that stands out in an overcrowded inbox?

Well, you’re in luck! We’ve gathered together some of today’s most effective subject line hits and oh-so-dreadful misses. Follow these dos and don’ts and you’ll be a subject line pro in no time!

DO Personalize When Possible.

Emails with personalized subject lines are 22 percent more likely to be opened. Personalization helps build rapport with your audience by showing them you know who they are, so leverage data points like first name, job title or location.

This simple tactic will make your subject lines more personal, tailored and engaging. But be sure that your data is clean and accurate or your personalization could hurt your results rather than improve them.



While there are no hard-and-fast rules with spam-trigger words, it’s best to avoid the most common offenders like free, guarantee and no obligation to avoid getting dumped into the junk folder.

Don’t stop there either. Also keep in mind what your readers may deem as spam. Even if you successfully make it into the inbox, you still need to convince your reader that you are genuine. In fact, 69 percent of email recipients report email as spam based on the subject line alone.

DO Add Pre-header Text.

The pre-header (aka preview or snippet) text is often used by subscribers as a prescreening tool to decide whether or not to open your email. Think of your pre-header text as an extension of your subject line — your “second subject line” if you will — and use the same strategies to optimize for both.  

Without pre-header text, email clients will automatically pull a snippet of copy from the first few lines in your email, including image alt-text. Sadly, it’s not common to see logo or hero image alt-text, or instructions like “View this email in web browser” or “Having trouble viewing this email?” These are wasted opportunities for marketers to reinforce their main message and encourage opens.  


DON’T Write in All Caps.

Do you enjoy getting yelled at by someone? Probably not and neither do your subscribers. Using all caps in your subject line is the digital equivalent of yelling.

Don’t mistakenly assume that a subject line (or individual words) written in all caps will grab your reader’s attention and persuade them to open your email. More than likely, they’ll ignore this disruptive tactic or even worse, mark your email as spam. In fact, more than 85 percent of respondents prefer an all-lowercase subject line to the alternative with all caps. Using all caps in your subject line is also a great way to trigger spam traps and end up in the junk folder.


DO Use Keywords.

Encourage subscribers to take action and read your emails by adding keywords to your subject line. Subscribers are more likely to read emails with subject lines that convey a sense of urgency and include phrases like “still time” and “expire” that make it seem like time is running out.

You should also place these keywords at the beginning of your subject line. In other words, get to the point quickly! This will help catch your reader’s attention and ensure the intent of your email is clear even if the subject line gets cut off.

Getting your emails opened is the first — and arguably the hardest — step to running a successful email marketing campaign. Without opens, there are no clicks, no leads, and worst of all, your beautifully designed email and great content will go unread.

More often than not, your emails are battling for your subscribers’ attention against competitors in addition to big brand names like Amazon and Nike. Give yourself the best chance of getting your emails opened by crafting subject lines that will engage, inspire and persuade.

Ashley Banek

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