Subject lines are the movie trailers of email marketing. They are a snapshot of what’s to come and should leave the audience wanting more. The difference is – subject lines usually get one shot to make their impression.

That’s why I say all subject lines should be “3D” – meaning they should pop out and grab your readers’ attention by being descriptive, direct and device-friendly. Many mobile readers will see long subject lines that wrap and push down your main content and some mobile devices only show up to about 25 characters. You want something that’s unique and grabs attention, but also concise enough to communicate the offer/benefit or call to action in around 40 characters. To help entice users to “read on,” it’s also best to use a “second subject line” in the pre-header of your email. The pre-header is where you often see “Click here to view as a web page.” This will show on mobile devices as well, so it should offer additional information, such as another compelling reason to follow your call to action. Here’s an example:


The subject line and pre-header text work together to make the call-to-open as descriptive as possible. The subject line example above is short and to the point, and using “action needed” should gain immediate attention. Then, listed in the pre-header is other vital information including the timeframe during which the reader should act. Together, they provide a great representation of the message to come.

Like movie trailers, if the content teaser (subject line) is misleading, people feel deceived. You shouldn’t trick readers into opening your email. For example, be careful when using “Re:” “FWD:” or “OOPS” in your subject lines. Some brands include these phrases to boost open rates, which it tends to do. But it can also damage subscribers’ trust if they think you are being intentionally misleading. On the other hand, it may make sense for some B2B campaigns, where you’ve heavily personalized the content, including using variable data in the from name/email address fields to make the client message appear as though it’s coming from his/her own sales representative. The bottom line is: Be genuine. If you consistently deliver great content and communicate compelling reasons to read your emails, subscribers will be more inclined to engage with your content over time. To keep with the movie metaphor: make your brand the respected director that consistently delivers crowd-pleasers.

Alright, you get the big picture. Now, for the nitty-gritty…

11 Tips for Writing Great Subject Lines:

  1. Use strong verbs to communicate the call to action.
  2. It doesn’t always have to be clever – informational is just as good (depending on the content).
  3. Every word should be absolutely necessary. Remember: 80 characters is your max and 40 characters is best practice if you have a high mobile readership.
  4. If you have numbers (like 10 Tips…), include that in the subject line.
  5. Try to avoid abbreviations unless they’re very commonly used.
  6. Exclamation marks can be left out most of the time. It can look spammy to email clients and hurt your deliverability.
  7. If it’s an offer email, include the window of time to claim the offer.
  8. If it’s a newsletter or part of a welcome series of emails, use a consistent naming convention so that your users don’t confuse the email with your other promotions. Adding the month or issue of a newsletter in the subject line is a great way to distinguish it from your other content.
  9. Take the time to develop something meaningful. You should create at least 2-3 variations of the subject line and pre-header before deciding which works best.
  10. Test using personalization to drive higher open rates (ex: first/last name variables). Remember that too much personalization can be creepy.
  11. In fact, test everything: what works with your audience? Does “DIY” work better than “Free download?” Does the % off or the sale’s end date in the subject line drive higher open rates? (Hint for emfluence Marketing Platform clients: The A/B split testing tool is perfect for testing subject lines. Check out the how-to in the Help section in your account!)

For other emfluence emsight posts on writing great subject lines, check out “Can I say ‘FREE’ in my subject line” and “symbols in subject lines.”

What subject line winners have you found for your own campaigns? Feel free to share in the comments!


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