7 Best Practices for Successful Email Subject Lines In 2021

Marketing

7 Best Practices for Successful Email Subject Lines In 2021

5d9f717441d3075498d306e6 Webp.net Resizeimage
by
Rachel Rockwell
on
May 5, 2021

Like most digital marketing industry averages, the criteria for “good” and “successful” email marketing changes often.

Is your open rate above 21%?

Is your click-through rate below 35?

(For more information on where your email marketing numbers should be, check out this handy blog.)

Then, there’s the all-important deliverability question: How’s your spam score? 

With spam filters constantly advancing, digital marketers need to know what triggers spam filters in order to increase email deliverability and land in inboxes. That’s only half the battle, though.

Email marketers also need to stay on top of your subscribers’ behaviors and interests in order to continue getting opened, because engagement (clicks, forwards, and replies) affects deliverability.

Both avoiding the spam filter and getting a campaign opened relies heavily on your subject line. It’s the first thing your subscriber sees in their inbox.

Download Free White Paper Now: A Beginner’s Guide to Email Marketing

With that in mind, here are the top email subject line best practices for digital marketing:

1. Keep them short

Subject lines should always be concise. Think of your email marketing campaign as breaking news, which means your subject line is the big bold headline.

Prioritize summarizing what’s in the email and why people should click. If you’re able to add a clever or creative twist (or even an emoji) without jeopardizing the length or integrity of the message, then go for it!

Another email marketing best practice? Always use the preview text. This is a great way to elaborate on the subject line.

2. Don’t use spammy words

Email marketing builds trust between your brand and subscribers. If your readers feel like your content is “spammy” or misleading, you risk being reported, sent to the junk folder, and notching higher spam and unsubscribe reports.

This is because a subject line often functions as a call-to-action. It inspires urgency or curiosity, but some words (474 to be exact) must be avoided. Stay away from words that could be described as shady, cheap, far-fetched, manipulative, needy, or sleazy.

Use this quick list that will definitely trigger spam filters to flag your email as suspicious:

  • As seen on
  • Do it today
  • What are you waiting for?
  • Order now
  • Click below
  • Bargain
  • Best price
  • Free (gift)
  • Satisfaction guaranteed
  • Incredible deal
  • Act now
  • Apply now
  • Instant
  • Limited time
  • Urgent
  • Earn extra cash
  • Free money
  • No hidden costs
  • Risk free
  • No fees
  • Score
  • Social Security Number
  • Spam
  • Unsolicited
  • Warranty
  • No purchase necessary
  • Winner
  • Free info
  • Free membership
  • Dramatically reduced

Email Marketing Tip: On the topic of spam, don’t write your subject line in all-caps. You’re basically yelling at spam filters to flag your message.

3. Don’t lie or mislead

The goal of email marketing is to build a rapport with your subscribers. Don’t jeopardize that trust by making a false promise in your subject line.

It may increase opens for that specific campaign, but your subscribers will feel irritated and misled. They’ll take it out on your future email campaigns by deleting them, flagging them as junk mail, or never opening them.

Because spam filters account for the engagement of your previous campaigns, these actions can seriously harm your email marketing efforts. Honesty is the best policy.

4. Ask questions

When executed properly, questions are examples of great subject lines. They often pique interest, and curiosity inevitably leads to an opened email.

So, how do email marketers properly execute a question as a subject line? Think about how your product or service could benefit the subscriber. Frame the question around that, like these email subject line examples:

60926e3495699f7a5285e5ea Qsq1MoLEjZTtK5Pl EVG6jG7X 009j8CJUicXhc70iuhec0QrDpaKUaDu62c8EYNNj KNePuFVUH2nJsldSFPpOdk4RgHLfGzLgo7qHmjvkCvcw1OsDktpB E2taCo8tMavwD0Gv
Yes, I actually do need a dress for a holiday party. While not all subscribers may be shopping for this seasonal staple, it helps that Show Me Your Mumu asked this question when many of its customers would specifically shop for a glittery party dress.
60926e336262b8be542d1906 HMjtCIViitd2QWm4d58 Tz1U7h7ZOI7gT9 WtUx5l9Amfpb5xZUywspIl6eXQRWw0SZF B ZMEK6zIw3cnSg O1McxCSDzumO MzEAPF7 UzSsxV8f5q3Xy0d6PrX5A6of PC3 R
I opened this email without a second thought, because most people won’t reject the opportunity to get a discount. Urban Outfitters shows us a great subject line example.

For newsletters, think about the overall question your main content answers, and ask that question as the subject line. Per usual, it’ll pique the curiosity of your email subscribers like these email subject line examples:

60926e331323a4b4b6875c88 JnUch 7kMVC4 V4AWlF Sga9KGw VCjmEnerHWk5D RmGFpI7s4Fwn Jgji5lPM Pf0bMQM3LLO2Hf9qbF4i3i8UFVR1UAgeeLex8DoVliLVb1hUh4L6J3u5wL9d5C29532FxiLR
What has pecan and pumpkin pie? Bon Appétit offers a textbook subject line example of questioning the subscriber into clicking.
60926e3313d78317f0b46d51 N580in1yPNpsqFQVIHsd3G70QxR0csFMmiqhEfD1oWWrme81aZHtub9rj05ZTgaHsf8t5EKstVhEFhZ5cIPsPMKSumORBaHdRGXW AEn9ngLDqusSQSvX3GcAhCA LzzLd K6Toa
Vanity Fair’s “The Hive” asked this question in their subject line. Indicating a respective article in the newsletter that answers it, this subject line example is sure to get a click.

5. Include deadlines

Be careful about inciting a sense of urgency with your subscribers. Don’t be misleading or fearful. It’s completely fine when it’s not aggressive, like mentioning that a sale ends tomorrow or counting down the days until a new product’s release or restock. These deadline-forward subject lines can successfully inspire your subscribers to open and/or click without triggering a red flag from spam filters.

6. Personalize

Thanks to email list segmentation, you can go beyond including just your subscriber’s name in the subject line. (Although that works well, too. Personalization over generalization every time.)

You can group subscribers by shopping behavior, geographic location, birthday, interests, age, gender, job industry, and so on. List segmentation allows you to send super-specific campaigns with super-specific email subject lines.

This best practice will ensure high open, click-through, and click-to-open rates, as well as low unsubscribe rates and the all-important low spam score.

60926e3386a340488e3397b6 GoFSEKYlKK1kHts4WVtJCUynwcAPJNCQ3MYrcc3Eq0V0nMWQH6aDE7y5Oq C8FhKic PjMRQWbLAS4TvHJxUA5M5HUD77uZxkqRpS6yG52mdz1pUnQ5i0ObOXHugIGbc4eZIP QV
Personalization tokens grab the subscriber’s attention. Live Nation Concerts does a good job of calling out the subscribers. The email body content even includes concerts they’re interested in based on location and previous ticket purchases.

7. Use a number (or two or three)

Go to your inbox right now. There’s likely an email with a subject line that includes a number. It’s the easiest way to create a good subject line. (In fact, it’s a best practice taken from content marketing for blogs.)

If it’s not a discount or price, the number is probably part of a list.

Numbers help capture attention, because they stand out among the sea of letters. Plus, content presented in a numerical list format is easy reading for most subscribers, which makes these emails highly clickable without being click-baity.

Lists are great for newsletters and emails that contain blogs. They also work well for promoting products and services, like Uncommon Goods (www.uncommongoods.com) does here:

60926e34eb6cb2eab142cd54 K2Bm4wVymp LT0urW7Two1U3lrbvaazVVGZMY5uiQ48EYaOsQb4 3pN26dcp5BJs T4SkKNFx4LtOaaSGQRfdWMOW9Tlapwh1oacZ0DQM8wwufx76yqHd7xGthj5MCsmfNGe33Vc
The gift-giving shop promotes 15 items in the subject line. In the body content, there’s a brief blurb on why each potential gift is unique. Ideally, subscribers would open the email, find an interesting  item, click on the link, and make an online purchase.

If you have the opportunity to use a number in the subject line, take advantage. Save those AP Style rules for blogs when it comes to dates, prices, discounts, days/hours remaining, and  more.

Using numbers in emails will also save you precious character counts within the subject line. Short and sweet, number-driven lines grab subscribers’ attention and subsequently increase the email campaign’s engagement. This helps boost deliverability for future campaigns.

To wrap it up

Like sender names, subject lines can both negatively and positively impact your email marketing campaigns. These best practices are generally successful, but to ensure they work for you, it’s important to keep an eye on your analytics and A/B test. The open and click-to-open rates from subscribers will let you know whether your subject line has truly succeeded.

To learn more about the basics of email marketing, download A Beginner’s Guide to Email Marketing by Mirabel’s Marketing Manager. Click on the button below to download your copy:

A Beginner’s Guide to Email Marketing

A free white paper with tips and best practices to help make your email marketing efforts successful

Download it now

Ready to close more deals with less effort?

Try the Marketing Manager FREE for one month.

Request Free Trial

Subscribe