The Do’s and Don’ts of Email Subject Lines

Introduction

Your email subject line is the first impression that determines whether your message gets opened or ignored. It’s a small piece of text with a big job—capturing attention, sparking curiosity, and inspiring action. Yet, many brands still overlook how powerful subject lines can be.

Let’s break down the essential do’s and don’ts of crafting email subject lines that actually work.

The Do’s of Email Subject Lines

1. Keep It Short and Clear

Most users check emails on mobile devices, so shorter is better. Aim for under 50 characters to make sure your full subject line is visible.
✅ Example: “Exclusive Deal: 20% Off Ends Tonight!”

2. Personalize When Possible

Adding a recipient’s name or relevant detail can make your email feel tailored. Personalization increases open rates because it speaks directly to the reader.
✅ Example: “Lily, your weekly marketing tips are here!”

3. Create Curiosity—But Stay Honest

A little intrigue can go a long way, as long as your content delivers what the subject line promises.
✅ Example: “You’ll Never Believe This Email Marketing Trick”

4. Use Action-Oriented Words

Start with strong verbs that encourage readers to do something: Discover, Unlock, Join, Save, Learn.
✅ Example: “Unlock Your Free Social Media Guide”

5. Test Different Variations (A/B Testing)

Even a small change in tone or word choice can impact open rates. Test multiple subject lines to see which version connects best with your audience.

6. Add Urgency When Relevant

Creating a sense of urgency encourages quicker action—but don’t overdo it.
✅ Example: “Last Chance to Register for the Webinar!”

The Don’ts of Email Subject Lines

1. Don’t Mislead Your Audience

Avoid clickbait or exaggerated claims. If your email doesn’t deliver on the subject line, you’ll lose trust quickly.
🚫 Example: “You Won a Free iPhone!” (when it’s actually a promo link)

2. Don’t Overuse All Caps or Excessive Punctuation

Using too many capital letters or exclamation points can make your email look spammy.
🚫 Example: “READ THIS NOW!!! LIMITED OFFER!!!”

3. Don’t Make It Too Long

Long subject lines get cut off, especially on mobile. Keep your message concise and impactful.
🚫 Example: “Our New Exclusive Summer Collection Just Dropped and You’ll Love Every Piece”

4. Don’t Use Spam Trigger Words

Words like “Free,” “Win,” “Cash,” or “Buy Now” can trigger spam filters. Use subtle phrasing instead.
🚫 Example: “Win Big! Free Bonus Inside!”

5. Don’t Forget to Match Tone with Your Brand

Your subject line should reflect your brand personality. A playful brand can use humor, while a professional brand should sound authoritative and trustworthy.

Pro Tip: Preview Text Matters Too

Your preview text (the line visible next to your subject) should complement your subject line. Think of it as the “second hook” to reinforce your message and drive curiosity.

✅ Example:
Subject: “Ready to Level Up Your Emails?”
Preview text: “Here are 5 quick tweaks to boost open rates instantly.”

Conclusion

Crafting great email subject lines is both art and strategy. Keep them short, clear, and true to your message. Avoid spam triggers, test regularly, and always think from your audience’s perspective. When done right, your subject lines become the gateway to higher engagement and stronger customer relationships.

FAQs