13 Best Practices for Email Subject Lines

In an email marketing campaign, your subject lines are essential to success.

Subject lines tell your recipients what to expect from an email, whether that’s promotional offers, free stuff, or information.

But if your subject line doesn’t get recipients to open your emails, then they’re not working. The good news is that you don’t have to rely on guesswork. Instead, use these 13 best practices to optimize your email marketing subject lines for consistent, strong results.

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1. Concision

The KISS principle — Keep It Simple, Stupid — is one of the most iconic sayings in business. It applies to sales pitches, marketing strategies, boardroom meetings, and just about everything else.

That includes email marketing.

In email, brief subject lines get more clicks. That’s because you can only have so many characters in a subject line before it gets truncated, just like with Google search results.

Plus, with the huge rise of mobile email usage, you can bet that lots of your recipients read your messages on their phones.

That gives you even less space in a subject line, so you have to choose your words carefully.

If you can convey an idea in three words, do it. Don’t jump to five words to add needless description. Write a subject, verb, and maybe direct object — then use it!

2. Human email addresses

A human email address is a proven method of getting more people to open your emails.

Human email addresses have recognizable names instead of generic, “robotic” names.

For example, recipients are much more likely to open an email from an address like [email protected] than [email protected]


In a nutshell, no one wants to talk to a machine. It’s the same idea as calling a customer service line — customers want to talk to a person instead of an automated voice.

This may still sound a little strange since email marketing is almost always a one-way conversation (unlike customer service interactions).

But while that may be true, it doesn’t remove the desire for a human element.

Emails from addresses like [email protected] might look like spam. Emails from [email protected] look like messages from a friend or acquaintance — or at least an actual person.

This practice comes with the bonus of allowing recipients to reply directly to someone at your business. So if they click the reply button, they won’t send an email to a catch-all address — they’ll reach an actual person who can help them.

The bottom line is that email marketing needs to be personal.

And speaking of personal…

3. Personalization

Personalization is the process of changing the content of your emails to appeal specifically to certain individuals or groups based on your company’s data.

That data could be demographics (information about consumer groups) or firmographics (information about employers), both of which are excellent starting points.

You start by writing a generic subject line that you like.

Then, you tweak it depending on the data you have on different individuals.

For example, if you’re sending an email about updates to your B2B marketing software, you want to approach clients in the healthcare sector differently than clients in the heavy machinery industry.

Those subject lines could differ in a word or two:

  1. How our updates affect your healthcare office
  2. How our updates affect your equipment dealership

Or they could be completely different:

  1. 3 ways we improved private practice marketing
  2. The #1 upgrade we made to your dealership software

Either way, you’re grabbing the attention of specific people in different industries by showing them that your information is relevant to them.

Along with a humanized email address and concise wording, you have a winning email marketing strategy already.

4. Tell, don’t sell

The people in your email marketing lists are thinking about becoming your customers — otherwise, they wouldn’t have signed up.

With that in mind, you don’t have to sell them on your company or products as much as you did when they first heard of your brand.

Instead, you need to tell them how your business can help them.

Your subject line doesn’t have to tell recipients all of the information on your equipment spec sheets or every single detail of your upcoming sales.

But it should tell them how they can benefit from reading your email.

So instead of listing out benefits in your subject line, you can say something like “New product — specs inside” or “Our sales calendar.”

These phrases are generalized, but they’re just specific enough to tell someone what’s in your message — and it doesn’t clog their inboxes with sales text.

5. Say what’s inside

Along with the previous practice, it’s essential that you tell your recipients what’s actually in your messages.

This goes hand-in-hand with telling instead of selling, but it goes a step further.

That’s because it’s important to provide enough detail in a subject line that subscribers know what they’ll gain by opening your email.

For example, if you’re an online retailer with 1000 different departments and a catalog of 50,000 products, the subject line “Sale!” wouldn’t give enough information.

But a subject line like “Electronics sale!” or “Back to school sale!” would be perfect.

To succeed with email marketing, your recipients have to know what to expect — otherwise, they won’t click.

6. Timing

Timing is crucial in email marketing, and that doesn’t just refer to the times you send your emails.

It also refers to how you word your subject lines to work with the time you send them.

For example, travel websites can reach out to their users based on their viewing history. If lots of your users have looked at fine dining restaurants for two, you could send an email on Wednesday or Thursday evening saying “Romantic hotspots for weekend dates” or “Fine dining without a reservation.”

This appeals to your target demographic by giving them enough time to make plans (two or three days), showing them interesting places, and giving them date ideas.

By timing that email just right, you show your recipients that you know them and you care about their interests — all from your subject line.

7. Strong verbs

Strong verbs are essential in all forms of marketing.

Strong verbs are action words that convey a precise idea in as few syllables as possible.

The most popular strong verb in English is “get.”

“Get” tells someone exactly what’s about to happen — they’ll receive something, and it’ll be theirs.

It’s also only three letters long, making it one of the strongest short words in the world.

But you can use other strong verbs as well, depending on your needs.

  • Amplify
  • Attract
  • Create
  • Discover
  • Expect
  • Maximize
  • Send
  • Start
  • Tailor
  • Test
  • Upgrade

In alphabetical order, these are just 11 of marketing’s most popular strong verbs.

When you use them in your subject line, they can work wonders.

8. Urgency

Urgency is important in marketing. If someone doesn’t think they have to get something done now, then they’ll probably never do it.

You can bet that every single one of your email recipients leads a busy life. So if you want to get their attention, you have to light a little bit of a fire to get them moving.

Words like “soon,” “fast,” and “quickly” are all great to use in email subject lines, especially if you want to move inventory or get new customers during a promotion.

You can also use tried-and-true phrases like “Act now” or “Start today” to nudge your recipients in the right direction.

This time-sensitive wording encourages your recipients to get something done as quickly as possible rather than waiting to do it after they finish something else.

That way, they actually convert from your emails, and your business continues to grow.

9. Appreciate recipients

Everybody likes to feel special. Even more, everyone likes to feel appreciated.

You can do both by crafting your subject lines with words like “Exclusive” and phrases like “Just for you!”

These may seem like minor additions to an email subject line, but they elicit emotion from your recipients. That’s valuable to any business because it helps forge a relationship between you and your recipients while encouraging them to buy.

By showing that connection to email recipients, you can earn customers for life.

10. Numbered lists

Numbers are a staple of modern email marketing. They give recipients an outline of an email’s contents so they can follow along as they read.

This is the same principle used in lots of blog posts and articles. With a numbered list, readers can guess how long an email will be before they open it.

Then, they can gauge their progress as they read.

That reaction is valuable to marketing and sales, since giving subscribers accurate expectations means they’ll be more likely to read your entire email.

11. Humor

Humor is an effective way to grab someone’s attention — but it has to be tasteful.

Humor-based marketing is most often used in traditional advertising, especially television commercials. It works best for brands that promote a relaxed, leisurely, everyday lifestyle, like beer or snack foods.

While humor may not be a good fit for your brand, think of a few ways to incorporate it into your email subject lines. A quick setup to a joke could make the difference between a click and a reflexive delete.

When you use humor, you’re going out on a limb. And depending on your audience, it can either work really well or bomb really badly.

But that risk is always there with humor.

Your best bet for success using this strategy is to remember that the basis of humor is subverting expectations. So if you set up a certain sentence or phrase with your subject line, go the other direction in your email body!

For example, you can subvert someone’s expectations by using a headline like “We have a problem…”

Then, your email body can start with “…we have too much inventory, so we’re selling it at half the cost!”

Is it a perfect joke? No. And you probably won’t make a perfect joke with email marketing.

But subverting expectations can at least elicit a sense of surprise, if not a laugh. So give it a try and see how it works for your business.

12. Preview text

This best practice is pretty self-explanatory.

If you’re going to send emails to a list of recipients, never block preview text.

Preview text shows your recipients what to expect when they open your email. They can see the first few lines, which tells them they can trust the contents.

Plus, it gives you the chance to attract your recipients with the first line of your body text and then some. It’s like a bonus subject line that gives you the best chances of success.

13. A/B testing

Finally, the best way to optimize your email marketing subject lines is with A/B testing.

Find a software provider that works for you and track the results of each email you send. Use different subject lines, and note the strategies you used in each line.

Then, look for patterns in your most successful subject lines to see what works for your business.

Those patterns will show you the best ways to connect with your current audience — and different segments within that audience.

With that in mind, A/B testing is one of the most important parts of your email marketing campaign. Without it, you’ll have a much harder time figuring out the best ways to approach your email marketing recipients.

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WebFX is a premier email marketing agency

If you want more people to open your marketing emails, WebFX can help!

We’re a full-service digital marketing agency with more than a decade of experience in Internet marketing. We know the best words to use to get people to open certain emails, and we also know how to find new words, phrases, and lines that work best for your business.

Are you ready to get more customers?

Contact us today to set up an email marketing strategy for your business!