5 Best Practices For Email Subject Lines From A Seasoned Email Marketing Copywriter

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subject lines

If you ask yourself what the most important part of any email is, your mind might jump from the design to the body copy. Or perhaps you thought of the banners and call to action buttons? The most effective email is a fine tuned combination of many different factors, but the truth is that none of that matters unless it is OPENED. You have just a few seconds to grab the recipient’s attention, and research has shown that almost half of all emails are opened based solely on their subject lines.  So it’s important that you get the subject lines right to begin with. Earlier we shared with you 200 Best Email Subject Lines to help you get ideas at the ready and now we get into the “how” to! As the head of copywriting at Hustler Marketing and someone tasked with writing and supervising hundreds of subject lines day in day out, here are my top best practices for email subject lines that will help your marketing emails pack a powerful punch. 

1. Subject Line Best Practices: Use Emojis (with care)

On average, emojis do work to increase open rates – when they are on brand. But proceed with caution, as there are three important factors to consider before you start throwing smiley faces around like confetti:

Email Subject Line Best Practices: Emojis


  1. Consider Your Audience: In general, emojis resonate more with females and a younger audience.
  2. Consider Your Choice: Ensure the emojis you use are a) on brand and b) provide relevant information about the content of the email. Generic emojis tend to have the opposite effect and can harm your open rate. 
  3. Consider The Placement: There are an increasing amount of recipients reading emails exclusively on mobile devices. In order to grab their attention, bear this in mind when you play around with the placement of the emoji.

2. Subject Line Best Practices: Personalization is Powerful 

Email Subject Line Best Practices: Personalization


Personalization is a key way to build a sense of familiarity and rapport with the recipient. It ensures they feel the email is relevant and important. 

The most obvious way to foster subject line personalization is through first name inclusion, but when that data isn’t available you can turn to the use of user-centric language to achieve the same results. 

Similar to your body copy, adopt an 80- 20 RULE: where 80% of your copy is written in the second person (i.e., “you”) and no more than 20% is written in the first person (i.e., “I” or “we”). Always ensure the copy answers the ever important WIIFM (“What’s in it for me?”) consumer question.

3. Subject Line Best Practices: Highlight the Value

Your subject line should clearly communicate what the email is about so that the recipient can gauge its importance and prioritize opening it. I.e. use your subject line to indicate the key value. 


  • Treat your subject line like the trailer to your email: A succinct, straightforward summary of the offer.
  • Focus on one valuable take away: Don’t muddy the waters by trying to offer too many things up front. Lead with one strong offer and then once they’re hooked explain the rest of what’s available inside the email.

4. Subject Line Best Practices: Create FOMO

Email Subject Line Best Practices: Scarcity

The two main tools at your disposal when creating a sense of FOMO in your subject lines are URGENCY and SCARCITY.

Email subject lines which convey a sense of urgency (those that include a time-sensitive deadline, for example) generally perform better than those that don’t. Likewise, scarcity-driven subject lines (“Limited Stock!” for example) can convince subscribers to make faster purchasing decisions. Used correctly, both these tools can give your recipients a reason to click immediately without using spammy or misleading phrasing.

5. Subject Line Best Practices: Adapt a Mobile Approach

Every year, the number of consumers who use a mobile device to check their email increases sharply. It’s important to adapt your subject lines for this move to mobile so your messaging doesn’t get missed. Here’s how:

  • Keep Copy Short: Different mobile devices show a different amount of characters on the screen, but rule of thumb is around 25 – 30 characters. If you need to work outside of this limit, ensure that you put the main message at the beginning of the subject line so that it is not missed.
  • Optimize Your Pre-Headers: They are often more prominent on mobile devices than on computers. Ensure the pre-header leads on from the subject line and works to incentivize the recipient to open the email. 

If your emails aren’t getting opened, they aren’t getting read. Catchy subject lines that convert are just a part of the email strategy and customized marketing plan our specialists can create for you. Get in touch today. 

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