20 Best Practices to Create Catchy and Effective Email Subject Lines In 2025

"First impressions last."

All of your appearance and demeanor are taken in, oftentimes judged, in those first few seconds right after you are introduced to another individual or a group.

The same is true for emails.

And it's the subject lines that we judge, not the entirety of the email. The same way we judge each other in those first few seconds of meeting, without really knowing the other person entirely.

It's what makes us decide if we're going to open to read the rest, or it goes straight to trash.

Or worse, tagged as spam.

This is why email subject lines are crucial. You may have written a stellar email, full of wit and value.  No one will look twice at it if your email subject line is as dull as the email's contents are sharp.

Following are the best practices in creating email subject lines that guarantee your emails will always be well-received:

1. Short

If you can make it sweet too, then go for it. But do make it short and on point.

Don't wax lyrical about your email too early in the game. Most, if not all of us, read emails from our mobile devices. With a regular inbox showing just about 60 characters, and mobile devices showing less at 25 to 30 characters, shorter email subject lines are the way to go.

It's going to take some creativity in crafting a short but interesting email subject line. You can make it about 45 to 50 characters long, but the long and the short of email subject lines is to keep it short.

Here are two examples of short and direct email subject lines:

Mark’s email on why people buy stuff has a subject line that tells exactly that. 36 characters in all.

Opening the email, you get exactly what it says on the subject line:

“14 Mobile Apps to Create Branded Visuals”. 40 characters.

And inside, we get the link to that content and a few more:

2. On Point

If your email subject line is short, then it's most likely to be on point.

This answers the question : What is the email about? More importantly, what value does it bring to your subscribers? What's in it for them to read your email?

Looking at the above examples, you'll see that both senders didn't waste valuable character count on anything that their email isn't about. They said in as little word as possible what you will get from their email and delivered exactly that.

Making subscribers aware of the valuable information in your email helps increase open rate. You have to be clear about this at the onset, and if you are, then your subject line will show it: it's going to be short and on point.

3. Curiosity

It seems like it's becoming more and more of a tall order, doesn't it? An email subject line that is short, on point, and now... Sparks curiosity.

But that's one of the reasons why you're keeping the email subject line short: to arouse curiosity. Yes, you're telling subscribers what the email is about, but by keeping it to a certain length, you're still keeping most of the email's content in the email itself.

Get them curious enough to want to open the email to know more. Like the following examples:

Mark Ling might just be the master of this game. His email subject lines are long enough to keep you wanting to know more.

And his email delivers exactly what it says:

4. Urgency

This typically applies to product launches and sales. If a sale is about to end, or it's only open for a specific number of hours, which they usually are... Then let your subscribers know.

And let them know right away.

It'll be difficult to do this for effect as the actual content of your email needs to have this limited-time-only information. But even if you can twist the subject line to give it a sense of urgency, don't. That is misleading and can cause you to lose your subscribers' trust.

It doesn’t always have to be offers or promos. . It can be information like webinars or FB Lives that is available for a number of hours only.

5. Creative

Keeping your email subject lines interesting and within a specific length is going to require some level of creativity. If you have that in spades, great.

If you don't, let puns and other creative wordplays guide you.

And if you really can't give it a creative twist, then don't. Stick with the other best practices here that you can do, and you'd still have a unique email subject line that gets those clicks.

This isn’t the best example, but the use of words is creative.

The subject line below is still acceptable, but could definitely have been written better. Maybe something like, “Our New Reports Will Make You an Alpha”.    

Here is a wordplay on CALM:

6. Compelling Questions

If you're having trouble phrasing the email subject line, try putting it into a question.

Ask yourself: what is it about your email that your subscribers would find interesting or valuable? Your subscribers are more likely to click and open your email if they think that you have the answer to what they need to know.

The question on Mark’s email subject line is something that marketers always ask. Opening the email gives the subscriber several answers to why they get clicks, but not sales.

The question is somewhat rhetorical, but in a sea of other emails, it’s able to grab your attention and your click. It’s a promotional email of course, but it starts off with a short message reminding subscribers that beauty is being kind to yourself and to others.

7. Use Numbers

Numbers help shorten email subject lines without changing or damaging its message. They contribute to a higher open rate, as Yesware found out in their study.

Using numbers makes it easier for you to come up with an email subject line that subscribers are more likely to find immediately interesting. It's "Top Traffic Strategies" as opposed to "Top 3 Traffic Strategies".

Using only numbers on the subject line, it’s creative, short and intriguing. Going into the email, it actually talks about using “Pattern Interrupts” when writing copy for ads, videos … and emails. You end up with an interesting copy that guarantees clicks.

This is the more classic way of using numbers in email subject lines:

8. Timely and Relevant

Celebrity names and other trending bits of information can get as much attention and clicks as puns and wordplays. If your email has to do with or is related to a popular celebrity or a trending topic, you can create a subject line that refers to them.

Make sure the content of your email references these celebrities, memes or events. Otherwise, your subscribers will see that you're just after their clicks, and you don't want that.

Samsung was trying to get people to sign up and preorder their Galaxy Fold phone, and they got the uber-popular KPop group BTS to promote it.

They’re definitely going to get top billing on the email subject line:

9. Preview Text

Preview Text is that line of text that appears on the Inbox. It's either on the side of your subject line, or right underneath it.

The preview text is like a blurb or a teaser to what is inside your email. The email subject line is like the movie's main title and the preview text is the trailer. It's a main header and subheader kind of thing.

That said, make good use of the preview text by putting in a brief but interesting description of what subscribers can expect to find inside the email. Don’t repeat what is already in the email subject line, rather, create a different sentence that expounds on the subject line, as shown in the following examples.

Email subject lines don’t need to be elaborate. Preview texts can be just as on point.

Canva doesn’t leave their subscribers guessing.

10. Subject Line Real Estate

We can't stress enough that it's in the best interest of your emails to have subject lines that are straight and to the point, but that doesn't mean you don't use all the available space for your subject lines and preview text.

As with the above examples, it's best to maximize the space provided as much as you can.

11. NO False Promises

Contrary to that popular saying, promises are not meant to be broken. It's the same as making a commitment and then not following through. Broken promises result to broken trust and that in turn, give way to broken relationships.

It's exactly the same way with your email subscribers. Losing trust could mean an unsubscribe, and that would be such a waste after the effort you put in trying to get traffic and subscribers.

You can give words a creative twist so you can have attention-grabbing subject lines, but you can't mislead subscribers. If you tell them that your email is about oranges, then there better be, at the very least, a mention of oranges in your email.

12. Personalize

Don't miss the opportunity to make the email more personal. If you can put in your subscriber's name on the subject line, then go right ahead. It will certainly grab their attention and let them know right off that the email is for them.

You might have received emails from shops and banks you frequent on your birthday. Most of the time, it’s only to wish you well. Some offer discounts as a gift. This is a classic example of personalizing subject lines and the emails themselves.

You get that click , and hopefully, get them to spend too. Just by making it a little bit more personal.

When applicable, take it a step further and localize it: refer to the subscriber's location in the subject line. If the email is about a list of coffee shops within the subscriber's city, say so. "10 Coffee Shops in Seattle and Beyond" is more interesting than "10 Coffee Shops Around the US".

I go by CL, and yes, I do have a Galaxy Note 10+.

I am on a first-name basis with Dropbox.

13. Segmentation

Email Autoresponders are sophisticated now. They allow in-depth segmentation, the kind where you can set up different marketing funnels for a list of subscribers depending on their interests, location, purchase history and a whole lot more.

A good example are these fashion retail brands. You subscribe to their mailing list to be updated when a certain style of shoes are back in stock. They take note of that preference and then add you to their segment for shoes and so you get emails when other kinds of shoes are available.

Segmentation helps you tailor both email subject lines and the email itself to the group of subscribers you're sending them to. This highly-relevant email campaign not only succeeds in getting a high open rate, it succeeds at getting subscribers to spend too.

This special offer is only available to owners of Galaxy Note 10+.

The subject line is nothing special, but all subscribers who had the same birthday got the same email with the same offer of a 20% discount on books.

14. Make them feel special

Or that they are a part of a community, an exclusive group. Give subscribers that feeling that they are included in something exclusive.

Adding their name to the subject line is great. Take it further and make them feel they are more.

Of course, when you do make the subject about your subscribers, then the content has to relate to or show exactly that.

 I was curious about what they meant that it’s really all about me. Opening the email, they gave suggestions on how I can better take care of my skin (using their products of course!), and at the end of the email, the sender said “elevating YOU is my ultimate goal.”

So the email really was all about me.

This series of emails is not necessarily about making the subscriber feel special, but the way it was worded implies a significant relationship. “Are we breaking up?” versus “Do you want to unsubscribe?”

It’s sent only to subscribers who have not opened his emails so there’s definitely segmentation there. It’s personal too, along with it being obviously well-thought-of and to the point.

15. Sender Name

..You'd notice in the previous examples that the emails are mostly from well-known brands. In one hand they don't need introductions, but on the other, wouldn't it be better if you got an email from someone within the company? Like, "Theresa of Ellana Minerals" as opposed to just their brand name?

More and more email marketers are using this personal and friendly approach of putting a name of someone in the company. It helps make the email look less spammy, and more from an actual person that you can reach out to if you have questions.

16. Use Call-to-Action Words

This is the same as using call-to-action words in your sales page or review pages. You want them to open your email, then use words that will compel or persuade them to take that action.

You could get right onto the offer. Make that sale announcement right from within the email subject line. But be sure to leave a few important tidbits for the rest of your email.

17. … and Power Words

 As there are words that you shouldn’t use, there are words that you should. “Power words” are similar to action words, but they capture attention rather than compel action.

Power words are about triggering emotion. Curiosity among the top ten. Words like “simple”, “fast”, “sensual”. These words, while not inciting action, do invoke emotion that may sway your readers to click on that email.

You’d find plenty of lists of power words to use. They don’t always have to be in your email subject line, but having them there is a good extra.

18.  But not these words …

There are words that spell S-P-A-M , as there are lists of power words and call-to-action words, there are lists of words that you are to steer clear of.

Words email providers hate:

• Free
• Credit
• Cash
• Offer
• Act now
• Limited time

Avoid filler words out too: very, basically, just.

It circles back to Best Practice #1: Keep it short. You have limited space, and you want only the best words filling it.

19. ... and Other Spammy Tactics

There are other ways for your email to land in the Spam and Junk mail folders even if you use the right words, and that is by doing any of the following:

USING ALL CAPS

Overdoing the exclamation marks!!!!!!!!!!!!!

Using @#!**^$!@ expletives

g3tt1n9 2 Cr8ive with numbers and characters

The same way that you won't do that above when speaking with a co-worker or a friend through chat, you shouldn't do the same when sending out emails to your subscribers. Use the right words to make your email subject lines interesting.  

20. Constant Taste Test

The only way a chef can know for sure that his dish tastes good is to taste it, and have other people taste it too. It's the same with email subject lines. 

It may look like the perfect email subject line for an email with great content, but it would still have a 50-50 chance of NOT getting opened. Regardless of how well-written an email subject line is, it is still up to the recipient to decide if it is good enough to click. 

The only way to know just how effective an email subject line is to test it. You can send one version to one group and another version to a different group. Then see which one gets a higher open rate. 

It's trial and error, and overtime, you will get a feel of what works for  your subscribers and what doesn't. 

Following all the above best practices don't guarantee opened emails 100% but following them will ensure that your emails land and stay in the Inbox. If they do, then you have a higher chance of getting them opened and keeping your subscribers. 

What do you think is the number-one practice to follow for email subject lines? What have you had success with? Do share — I’d love to know what has worked for you and what hasn’t.

P.S. If you want to learn more about email and newsletter strategies, be sure to check out our free lessons on email marketing.