Increase your open rate with these email subject line tips

April 25, 2019
Increase your open rate with these email subject line tips

The competitive world of email marketing is hard enough when you’re working to make the content in your email as sharp and effective as possible. Add in that your subject line is perhaps the element that needs to work the hardest, it becomes an even trickier task to get it all perfect.

We all scan through plenty of emails every day to know what to avoid when writing a strong subject line. But when it comes to writing a good subject line, what should you look out for and what are some of the best tactics for writing them? Read on to find out…

Size Matters

The first thing to think about is the length of the subject line. While using a desktop allows you to write a long subject line, remember that over 80% of your traffic will come through via mobile. Using mobile apps makes subject lines much shorter so you have less space to play with. Eight words is the limit of how long you can afford to make the subject line, so don’t worry about the detail. Just focus on catching the eye to encourage an open.

Eye Catching

There are several options when writing a good subject line. If you work in an industry that can make offers, then this is a tried and tested place to start. Offers will always attract the reader’s eye away from other emails in their inbox. Make sure the offer is appealing too, 5% off isn’t going to encourage a click through for instance. Try and think to yourself, what would compel you to click through?


If you don’t have an offer to use then why not use time instead. Creating a sense of urgency in a subject line is a great way to encourage a subscriber to open the email there and then rather than look at it later. The chances are they won’t so try and push them for that click. It can be anything from something that will expire in 24 hours, to competition that you are giving them exclusive access to for a limited time only. Word of warning however, do not use this approach all the time, and make sure your email does contain what the subject line has promised. Not doing so will put people off opening them in future.


Click-bait has become incredibly popular thanks to social media and this isn’t a term we like to use but there’s a diet version that focuses more on piquing a person’s curiosity. Create a subject line that teases what’s within the email, encourage that open through clever language and not revealing the full story. Again, if the subject line stands out from the crowd because it sounds intriguing then you are far more likely to hold the users attention for longer.


As email systems become more and more complex and able to deliver more bespoke offerings, so personalisation becomes more important to email marketers. It’s a great idea to personalise your subject lines by the audience you’re sending to. By using preference centres and similar tools, email systems can now tell you if people are interested in the subjects you’re emailing about. Therefore the subject line can be more targeted towards those who want to hear about it rather than a general hit and hope style email.


Finally, and this isn’t something that everyone enjoys doing but why not try some emojis? They’ve become so ingrained in digital communication that it’s only right they can be used in subject lines. They are a great tool to help grab someone’s attention too. If you’re worried that the content might not catch the eye, throw some sirens or alert emojis to frame it and you’ll catch the eye far more than usual.

There is plenty to try out here, but remember, making your subject lines short and concise is the main objective. Mobile users dominate email opens now so it needs to work for them. Too long and they might miss the hook. Don’t forget to do plenty of testing too. Try subject lines with emojis and without, try them with calls to action or with more teasing lines. The more you test, the better informed you will be about what your audience wants to see!

Of course, we can do all the testing and subject line writing for you if time isn’t on your side. Contact us below and we’ll be happy to help!