Nailing the Subject Line: Best Practices to Get Your Emails Opened (and Loved)

You’ve spent hours crafting the perfect email—personalised content, eye-catching design, and a clear call-to-action. But none of that matters if your subject line falls flat.

It’s the first thing your audience sees; if it doesn’t grab their attention, your email might as well be invisible. ??

So, how do you write a subject line that opens your emails and makes your subscribers eager to read what’s inside?

Let’s dive into some best practices and top it off with actionable tips that’ll have your open rates soaring.

1. Keep It Short and Sweet (But Powerful)

Your subscribers are busy. They’re scrolling through their inbox at lightning speed, and long, drawn-out subject lines are likely to get skipped.

Aim for 6-10 words or 40-50 characters max. Get to the point quickly and make every word count.

Instead of: “Check Out Our Amazing New Collection of Summer Dresses That You’ll Absolutely Love!”

Try: “Summer Dresses You’ll Love”

Mobile devices often cut off longer subject lines, so shorter is better. Aim for something that stands out even in a crowded inbox.

If it doesn’t catch their attention in the first 30 characters, most of your audience won’t even read the rest of the subject line, let alone your email content. ??♂?

2. Add a Dash of Personalisation

Personalisation goes beyond just using a first name. Tailoring the subject line to reflect the recipient’s interests, past behaviour, or location makes your email feel more relevant and increases the chances of it being opened.

For example:

“[First Name], Your Perfect Workout Gear Awaits ??”

“Hey [First Name], Ready for the Weekend? ??”

Personalised subject lines are 26% more likely to be opened (source: Campaign Monitor). It’s like giving your email a VIP pass to the inbox.

3. Create a Sense of Urgency

FOMO (Fear of Missing Out) is real.

When people feel like they’re about to miss something valuable, they’re more likely to act quickly. Use urgency sparingly—too much can feel pushy—but when done right, it drives immediate action.

Examples:

“Last Chance: 20% Off Ends Tonight!”

“Only a Few Left—Grab Yours Now!”

Combine urgency with exclusivity for even more impact:

“Exclusive for You: Flash Sale Ends in 3 Hours”

4. Ask a Question

Questions naturally pique curiosity. They invite the reader to engage and consider their answer, which leads to them opening the email to find out more.

Need an inspiration? I’ve got you covered:

“Need a Break? Here’s How to Unwind”

“Ready to Upgrade Your Wardrobe?”

People love to interact, even if it’s just mentally!

5. Use Humor (But Know Your Audience)

A little humour can go a long way in standing out from the sea of boring subject lines. It shows personality and makes your brand more relatable.

Just be sure the humour aligns with your brand voice and resonates with your audience.

Need Examples?

“Oops, Did You Forget Something? (We Won’t Tell) ??”

“Ready to Treat Yo’Self? We’ve Got You Covered”

Humour is subjective. What’s funny to one person might not land with another, so know your audience and test different tones to see what works best.

6. Be Clear and Specific

While creativity is important, clarity is king. Your subject line should give a clear idea of what the email is about. If your audience knows what to expect, they’re more likely to open it.

Need some pointers?

“Your Guide to a Healthier You—Download Inside”

“New Arrivals: Shop the Latest Trends Today”

Clarity builds trust, and trust builds engagement.

7. Use Numbers or Lists

Numbers are attention-grabbing and make your subject line more compelling. People love lists because they know what they’re getting—a quick, digestible read.

A Few Examples:

“5 Tips for Better Sleep Tonight ??”

“3 Reasons to Love Our New Collection”

Odd numbers tend to perform better than even numbers. They’re more intriguing and feel less formulaic.

Try it out and see how your audience responds!

8. A/B Test for the Win

Even with all the best practices in the world, you won’t know what works best for your audience until you test it.

A/B testing different subject lines allows you to compare performance and refine your approach based on real data.

It’s like fine-tuning your email engine for peak performance.

9. Use Emojis (But Don’t Overdo It)

Emojis add a splash of colour and personality to your subject line, making it stand out in the inbox. But use them wisely—too many can feel gimmicky, and not all audiences appreciate them.

For Example:

“New Arrivals You Can’t Miss! ??”

“Ready for Summer? ?? Our Top Picks Are Here”

Test the placement of emojis (beginning, middle, or end) and make sure they align with the tone of your message.

Not all devices display emojis the same way, so check how they render across platforms.

Also, if you notice, all sendXmail ’s newsletter goes with a ?? emoji to quickly identify all our emails in our subscribers’ inboxes.

Morning Brew opens all their subject lines with a ?? emoji for easy identification.

Wrapping It All Up: The Subject Line Sweet Spot

Your subject line is the gateway to your email. It’s the first impression, the hook, the moment that determines whether your carefully crafted message gets opened or overlooked.

By keeping your emails short, personal, clear, and a little bit fun, you will ensure they stand out in even the most crowded inboxes.

Remember: A great subject line doesn’t just grab attention—it sets the tone for the entire email experience. So, take the time to experiment, test, and refine.

Your open rates will thank you!

Got a subject line hack that works wonders for you?

Share it in the comments—I’m always on the lookout for new tips to try!

BTW: this was first posted on my personal blog here.