Master Email Subject Lines With These 9 Tips

February 21, 2024

It's the first thing your recipients see when your email lands in their inbox. And it's going to play a huge role in determining whether or not they actually open your email. In fact, 35% of recipients make the call based on this one factor alone. Still, some marketers too easily throw email subject lines together with no thought, dismissing them as irrelevant.

Like everything else in digital marketing, with email subject lines, some approaches work while others don't. We'd like to offer you nine tips for how you can ace your email subject lines to see an immediate improvement in your open rate.

Keep scrolling!

What Is An Email Subject Line?

Email subject lines are brief phrases or sentences that summarize the content of an email and entice recipients to open and read it. They serve as a preview or headline for the email, providing a glimpse into its purpose or key information. In the sections to come, we will reveal 9 expert tips on how to create more engaging email subject lines.

Email Subject Lines for Pros: 9 Tips

1. Give a Glimpse of What the Email is About

People like surprises on their birthday. They don't like them in their email inbox.

They're busy, drowning in emails, and their attention span is minimal. This means that you need to craft your email subject line to reflect what the email is going to discuss.

This isn't to say that if you email your subscriber list about a sale on your brand's shoes, the subject line needs to be, "This email is about a sale on shoes." You can still get creative and have fun, but the point is that people should have an idea of what's going to happen if they click on and open that email.

2. Keep it Short

We mean it — short! Think five to seven words. The reason for this is that many people are going to be reading your email on their smartphones, meaning you need to make sure that your content is mobile-optimized. You've (hopefully) already done this with your website, and your email content is no different.

This means that you need to take care to get to the point and cut out any fluff/filler content.

Check out this example. In the first email, the subject line cuts off. In the second, it fits. It makes a difference.

email subject lines

Worst case scenario, if you're drafting an email on a desktop and don't know how it'll look for mobile viewers, send a test email to yourself and check it out on your own smartphone.

3. Avoid Email Subject Lines That Get You Flagged as Spam

Do you ever check your spam folder just for fun, to see what ended up there? You probably see a lot of subject lines like this:


" this you?!?!?!?"

"Buy now! Totally free and results guaranteed!!!!"

Notice any patterns? Anything in common? Lots of punctuation marks and words written in caps. Both are big no-nos. If this doesn't cause your email to automatically end up in the Spam folder, then you certainly run the risk of your recipients marking it as spam anyway.

Here's one subject line that landed this email in my Spam folder. While I can't prove that it's the punctuation marks that caused it, I have a sneaking suspicion. And here's the funny part: The sender is legit and someone I willingly subscribed to!

spam email subject lines

"But I want to get their attention," you say. And that's great! You absolutely should. But you need to find other ways to do it. For example, try adding an emoji to your email subject lines. Or...

4. Spark Their Curiosity

Humans are inherently curious. It's hard for us to resist a good mystery. So, if your email subject lines do something to pique their curiosity, you're going to grab their attention — and they're going to want to know more. This is one way to increase your open rates.

You can spark curiosity by asking a question or starting a statement that requires them to open the email to get the rest of it. For instance, if you're running a flash sale, a good subject line might be something like, "We know how much you love flash sales, so..." or "One day only - open asap."

You get the idea. In the first example, we get their attention by starting a conversation that's obviously about flash sales. But they won't know more unless they read the email.

The second example puts a ticking clock on the scenario and also includes a call-to-action (CTA), which is always a good thing.

And in both cases, we injected a little bit of FOMO in there. When you create urgency in your email subject lines, recipients will have a harder time ignoring you.

5. If Possible, Make it a List

People love lists. In fact, blog posts that are "listicles" with titles like "Top 7 Instagram Tips for Business" tend to have a higher click-through rate (CTR) and get great traffic.

This is because a list takes a bigger, more complex, complicated topic or task and breaks it down into more manageable, bite-sized pieces. It's essentially a step-by-step guide where you hold the reader's hand and walk them through something that's overwhelming them.

So, if you can turn your email subject line into a list, you might very well see an increase in your open rates. Of course, only do this if it's applicable and makes sense. As a side note, in general, numbers can really help your conversion rates. Do use numerals as opposed to spelling numbers out. It's...

"We love these 5 yoga pants"


"We love these five yoga pants"

6. Personalize Your Email Subject Lines With the Recipient's Name

Do you know what everyone's favorite word is? Their own name.

We've mentioned already that people's inboxes are bursting at the seams. Research finds that we're receiving well over 100 business emails a day, and many of them are beyond generic. Too many brands take a cookie-cutter approach, delivering the same subject line to every recipient and not bothering to customize it even a little bit.

You can make yours unique by adding a personalization token — like the recipient's first name.

When you create the email, you'll type something similar to this (depending on what tool you're using):

"Hey [NAME], our flash sale starts now!"

And when the recipient receives it, it'll look like this:

"Hey Megan, our flash sale starts now!"

Most email marketing software offers a number of personalization tokens, including the user's city. But their first name is a popular choice. It helps you appear more friendly and personable, and it shows your recipients that you acknowledge them as an individual.

7. Beware of Gmail's Other Inboxes

You've probably noticed that Gmail actually has three inboxes: Primary, Social, and Promotions. It looks like this:

gmail three inboxes primary, social, promotions

While there's nothing inherently bad about the Social and Promotions tabs, where do you think you want your email to end up?

Under Primary.

This is because when someone logs into their Gmail account, they land on Primary. This means they're much likelier to see your message there, compared to the Social or Promotions inboxes.

Gmail determines where specifically to put your email based on its content, and that includes your email subject lines. As a general rule of thumb, aim to make your emails sound as personal and non-promotional as possible. This will help you avoid Social and Promotions.

Note that this means that emails with language obviously conveying sales, offers, or promotions might trigger Gmail to send you to Promotions. Likewise, email subject lines focused on social media can send you to Social.

It's all in your wording.

Now, we understand that you won't always be able to avoid this. If you're running a huge sale, you'll likely want to include the word "sale" in your subject line at some point. And that's okay!

We want to remind you that going to Social or Promotions isn't terrible. It's not like getting sent to Spam. You just might not be quite as visible.

On the flip side, if your recipients are used to receiving valuable, high-quality content from you, they're going to want to read your email regardless of where it lands.

8. Remember the Preview Text

While it's not technically the subject line, it comes right after it, and it's just as important. It's the preview text — this thing:

email preview text

Some email marketing software has a specific field where you can type your preview text. In other cases, it's just going to pull the beginning of the email. In either scenario, the preview text is prime real estate, so you should take it seriously.

Think of it as another little glimpse into what the email covers. It should provide comfort and reassurance that if your reader clicks to open it, they won't be disappointed.

9. Run A/B Testing Regularly

We can't stress this enough. In fact, it's the most important point on this list and beats out everything else we've told you: Test everything.

The only way to know for sure that you're taking the right approach with your email marketing is to have various approaches to compare. You need to be comparing the results of Strategy A to the results of Strategy B.

Otherwise, you have no way of knowing.

Yes, putting the recipient's first name in the subject line typically helps, but that doesn't guarantee it's going to work for you. Test it.

Sure, some people love seeing emojis before they open an email, but your subscribers might feel differently. Test it.

Absolutely, FOMO often works like a charm, but that might not be the case for your email list. Test it.

Test, test, test! Constantly.

All great marketers know one thing for sure: They don't know anything...

... until they test.

Remember that you want to isolate one variable at a time, so with your email subject lines, you should only ever change one factor at a time. Otherwise, you have no way of knowing what change caused which fluctuation.

For instance, keep the text the same but use an emoji in Version A and leave it out of Version B. Or keep the text the same except use the recipient's first name in one and leave it out of the other.

You get the idea.

One more note about testing: Give things time. If you send one email with an emoji and you aren't happy with the open rate, don't automatically assume it was the emoji. Test things a few times, always in comparison to another version, and look for patterns over time. This is when you can really start to make decisions about what works and what doesn't for your company.

Frequently Asked Questions

Why are email subject lines important?

Email subject lines are crucial because they determine whether recipients open or ignore your emails, making them a critical factor in achieving high open rates and engaging your audience.

How long should an email subject line be?

Ideally, an email subject line should be concise and to the point, typically between 5 to 7 words or around 40 to 60 characters, as shorter subject lines tend to perform better.

What are some effective techniques for writing compelling subject lines?

Some effective techniques include using personalization, creating a sense of urgency or curiosity, incorporating numbers or statistics, and emphasizing the benefits or value offered in the email.

How can I avoid common mistakes when writing email subject lines?

To avoid common mistakes, ensure that your subject lines are not too generic, misleading, or excessively promotional. Additionally, avoid using all capital letters or excessive punctuation that may trigger spam filters.

How can I test the effectiveness of my email subject lines?

A/B testing is a great way to evaluate the effectiveness of your subject lines. Create multiple versions and send them to different segments of your audience to determine which subject line performs better in terms of open rates and engagement.

The Bottom Line

Remember that your email subscribers are human beings. They're living, breathing, sentient individuals. So, that's how you should treat them. Don't use the subject line to trick them and certainly stay away from anything "clickbaity."

Email marketing is a marathon, not a sprint. Get comfortable with testing, try different things, and keep a close eye on your analytics. Over time, you'll zero in on the email marketing strategy that makes the most sense for you.

Run your digital marketing like a well-oiled machine. e-clincher can help. Sign up for a free trial and experience it for yourself.

Start Your Free Trial

All in one powerful platform.
Start FREE 14-days trial
AI-powered social media management
monitor consumers sentiment
track & analyze performance