Email subject lines are the first thing that email recipients see in their inbox. It’s your introduction to the viewer, and it determines whether they will choose to engage with your brand or not. Those 40 characters could get someone excited to read your email or annoy them enough to send it straight to the junk folder. 

Subject Lines: Best Practices

Creative, compelling, and informative email subject lines capture the interest of recipients and encourage them to open. This decision is the difference between having the opportunity to speak to your audience and being ignored.

Subject Lines to Engage 

Engagement is all about delivering value or entertainment to your audience. If they’re convinced that your email has something they want, then they’ll open it. Your subject line is like a store window that entices passersby to enter and explore.

Use the recipient’s name to personalize the subject line

“Hi, [first name], are you looking for deals on a new couch?” Personalized subject lines are 22% more likely to be opened. If you have information about the person you’re emailing, use it in your subject line to warm your conversation.

Use referrals to create a sense of familiarity

“[Name of referrer] recommended that I get in touch,” lets your prospect know right up front that you have a mutual contact. It immediately establishes trust before they even open the email.

On how to create a referral program:

A Simple Guide for a High Impact Referral Program

Pique their interests with the promise of a question

“Question about _____,” can be a great subject line to increase opens since recipients will need to click to find out what it is you want to ask

Be very clear about what your email offers

People get annoyed at emails (and companies) that waste their time. Let your recipient know what your email offers and why they must open it. This is especially applicable if you have a special offer for them. Place the value upfront to entice the recipient. For example, “[eBook] 2020 Style Trends for the Chic Executive,” could be enough to get a busy corporate fashionista to open your email.

Don’t trick your recipients with a promising subject line and then underdeliver with the actual offer. For example, a subject line promising “50% off all items” creates certain expectations for your subscribers. Imagine if you only offer 50% off for a limited range of items — your subscribers aren’t going to trust you the next time you send a sales promotion.

A/B test your subject lines

Once you come up with a few subject lines that your team is excited about, A/B test them to see which ones are most effective with your audience. The customer knows best, in this case — let the data guide you.

Create a log of the A/B tests you run, the time you send the email, and make sure to document the performance of different subject lines. This will make your life so much easier!

On how to effectively conduct A/B tests: 

A/B Testing: An Introduction [INFOGRAPHIC]

Use shorter subject lines to be mobile-friendly and add emojis (when appropriate)

Space is limited in subject lines. If you want the entire subject to be viewable on mobile devices, the limit is 30-40 characters. Emojis have become more popular in recent years because they express a lot in one character, and they result in higher open rates. 56% of brands that use emojis in their subject lines have a higher unique open rate than competitors that don’t. Emojis help your email stand out in a crowded inbox, which is the first and most significant hurdle. However, it’s crucial to ensure that emojis fit the tone of your message and suit your brand before using them. For example, it would be off-putting if a funeral home used emojis, but it’s cute for emails about kids’ toys and dog treats.

For more on emojis (and the rules to use them):

Is Emoji Marketing for Your Brand?

Subject Lines to Re-Engage

Re-engagement email subject lines follow the same general principles as the engagement emails, but they come with their own unique features. Since marketers lose contacts to both unsubscribes and email list decay (industry experts estimate decay of 22.5% per year), it’s essential to maintain contact with the people on the list who still receive your emails.  Many of these subscribers ignore your messages, so you need an enticing email strategy to reconnect with these people and the power of strong re-engagement email subject lines.

This process will require a series of emails, not just one or two. One study found that 14% of subscribers who receive re-engagement emails read them, but the number increased to 45% for subsequent emails.  So, don’t be dismayed by your first attempt. Keep trying and test out the following best practices. When creating re-engagement email subject lines, it’s important to consider the recipient’s inbox experience. Often, the person lacks the time and patience to review all of their emails. Many of them have ignored your emails for months — maybe even a year. So, what will make them finally pay attention?

On how to re-engage your customers via email:

Re-Engagement Email Campaigns: Win Back Customers

Use a personalized, targeted offer to catch their attention

People will always notice when an email has their name in it. It signals that the sender knows them and that they’ve connected in the past. Something like, “Sarah — 50% off your favorite items right now,” might entice Sarah to click and see what she could get. FOMO can strike if she doesn’t click.

Celebrate an anniversary

ModCloth celebrates six-month anniversaries with a “treat in the form of a coupon. Instead of focusing on the negative, they can re-engage their audience with an enticing offer and celebrate their relationship. The anniversary provides a positive spin and just enough motivation to test the recipient’s sincere interest.

Use actionable or emotional words

Appealing to the recipient’s emotions can help to increase open rates significantly. Whether you use amusement, suspense, guilt, excitement, or another emotion, depends on your brand and strategy. People also respond to words that entice action.

Be BOLD and envoke FOMO

Your audience is already ignoring you, so you have little left to lose. Try the bold approach to catch your audience’s attention. You can lead with a big promise or offer and tell them that time is running out. Some examples might be, “Only 20 spots left! Sign up before Friday to get 50% off.” Or, you might go bigger with, “$1000 shopping spree or 50% off — click to see what you won.” 

Reference previous conversations to let them know it’s not SPAM

For sales outreach emails, subject lines like, “Here’s the information you asked for,” can boost open rates. It refers to a previous conversation or interaction with the recipient, so they know it’s not junk mail. And, even better, it’s something that they wanted, so they will be interested in getting it (and opening the email).

Finally, test the breakup email

If the contact is still not engaging with your emails, it’s time to consider cleaning them from your list. You want to know once and for all whether or not they should remain on your email list. If they continue to ignore you, it’s better to remove them, so they don’t pull down your engagement numbers. 

A subject line like, “Is it really over?” with a breakup email can push a contact to re-engage with your brand. Or you could try, “My final attempt.” Breakup emails are their own art form, so learn more about them in this useful resource from HubSpot

Final Thoughts on Engagement and Re-Engagement Email Subject Lines

Subject lines are vital to successful email marketing campaigns. The wrong one can earn you an unsubscribe and lose your contact forever. The right one can be the first step toward gaining a lifelong customer. Personalization and interest are the most essential qualities of a great subject line. Consider your brand personas and write subject lines that will appeal to their needs and interests. The deeper that you segment your audience, the more personal your subject lines and email content can become, and the higher the likelihood of success. Always test, analyze, revise, and test again to find the exact right balance for your unique audience. 

To learn more about email marketing:

Email Marketing: A Guide for Beginners [TEMPLATE]

Evi Katsoulieri
Author

Evi is the Email Marketing Associate at AdRoll. She is passionate about testing out growth strategies that enable users to leverage AdRoll capabilities across the lifecycle stages. In her free time, she enjoys traveling, cooking Mediterranean specialties and spending time with her dog.