7 Tips for Writing Engaging Email Subject Lines

When it comes to email marketing your subject line is the catalyst to creating a lasting impression. If compelling enough, your email subject lines are a ticket to standing out in one of the most competitive spaces in digital media: the email inbox.

In order to engage your unique audience and advance your business goals, your email must get opened as many times as possible. Consider these 7 tips and 7 tactics to help guide you in writing engaging email subject lines that people will want to open.

Tip #1: Optimize for mobile viewing

Today, 81% of all emails are now opened and read on mobile devices. Prioritize email layouts on mobile first and desktop second. Be sure to keep your subject line (and overall content strategy) short and to the point. This will help safeguard content from being cut off since mobile email apps only display approximately 35 characters of a subject line in the inbox view.

(Image source: Art Storefronts Blog)

Tip #2: Be concise and specific

Subject lines with 6 to 10 words are ideal in order to deliver the highest open rate. If you struggle to keep subject lines short and sweet, consider which words matter less and where you can remove frivolous details (e.g. “Your order is being processed” vs. “Order #1456873456 is being processed.”

That’s not to say that clarity should be overlooked at the expense of fewer words (specificity will always be more important than length). There will always be exceptions to this rule, e.g. with time-sensitive content that should include the timeframe even if it means adding length. No matter the situation, clearly communicate what the email content will deliver on to encourage the recipient to click through.

Tip #3: Use a familiar ‘From:’ tag

Sender names are the lowest hanging of the subject line fruits, but one of the most frequently overlooked. The email “From:” line can have as much impact on your open rate as the actual subject line. Ideally, these two work together to create clarity for the reader in terms of who the email is from and why it’s important.

Generally speaking, specificity is the end goal. This doesn’t necessarily mean you need a name in your ‘from:’ tag. You just want to sound as human as possible. Consider using the following formats: ‘[email protected]’ or ‘[email protected].’


Additionally, avoid using the common ‘no-reply’ sender name. Due to the number of spam emails people receive nowadays, there may be hesitancy to open an email from an unfamiliar address.

Tip #4: Leverage personalization tokens

Message Personalization is the number one tactic used by email marketers to improve click-through rates and performance. In fact, brands that personalize their email marketing see 27% higher click-through rates. Leveraging personalization tokens (e.g. name or location) in the subject line can create a sense of rapport.

However, studies have shown that personalizing the subject line with a recipient’s name can depress open rates. Conversely, personalizing just the email content can increase open rates and click-through rates. Consider personalizing your subject line with a city name instead of a recipient’s name to maximize your marketing efforts.

The personalization tactics you choose depend on your business goals, but this blog post can help you understand the how marketing personalization can help you keep up with customer demands.

Tip #5: Time it right

Sending an email at the right time with the right subject line can make all the difference in terms of increasing open and click-through rates. A great example of this can be seen with Quip, which sends an email reminder to its subscribers when their refill is preparing to ship. The brand clearly specifies what the email will entail in the subject line by saying “refill processing!”. But it also prompts the user to click-through with language to review additional account information.


Tip #6: Avoid using certain words

There are 2 kinds of trigger words to avoid using in email subject lines—words that trip spam filters and words that trip our own mental aversions. Fortunately, they tend to be similar—words that alert deals and offers. Unfortunately, if you are trying to promote a great opportunity, you have to contend with the fact that many marketers have used the sales and promotions tactic too many times now. Get creative, and remember that you’re ultimately selling a product, not a discount.

HubSpot recently identified a number of email spam trigger words to avoid, including:

  • Offer

  • Winner

  • Free sample

  • Special promotion

  • While supplies last

Tip #7: Segment your lists

Emails blasts that go out to an entire mailing list can be relevant and helpful for some, but not all. For example, a restaurant sending a list of local steakhouses to someone who eats a plant-based diet can cause confusion and frustration.

It’s important to create a personalized experience from information you already have on your customers (e.g. forms they’ve filled out, products they’ve purchased, personal preferences, etc.). Use this to segment your lists and exclude recipients whose interests or preferences don’t align with your messaging.

One final note on email subject lines…

You really need to be A/B testing. Period. No two marketer’s goals are the same and figuring out what works best with your specific audience is the first step to crafting a successful email marketing campaign.

Companies that A/B test every email see email marketing returns that are 37% higher than those that never do A/B tests!

Truth be told, there’s no silver bullet or magic formula for writing high-performing subject lines. While we can see the types of things people click on, that doesn’t mean we know what causes a subject line to get more opens than another. Experience and data can point you in the right direction, but the only true path to success lies in repeatedly evaluating and optimizing.

Don’t think of the following tips as an end-all-be-all to writing the perfect subject line. Rather, use these recommendations as a testing ground for writing potentially perfect subject lines.


Thanks for your interest in Zeta. To see a demo please complete the form.

Thank you!

Your request has been sent. We will be in touch with you shortly.