5 Rules for Writing Subject Lines that Work

It’s hard to write a good subject line. Let’s put that out there. Right now you could be sitting in front of a well-prepared email for your customers, ready to hit send, yet stumped by a few simple words. 

It’s a good sign you’ve stopped long enough to think about it because people will judge your email by its subject line. In fact, 35 percent of email recipients will choose to either open or ignore an email based on the subject line alone.

You don’t want to oversell and risk sounding like spam, yet you don’t want to be ignored. Subject lines demand a delicate balance, but don’t worry, it is possible to write a great one — and it’s pretty simple once you get the hang of it.

 Here are a few tips to help you on the way to inbox stardom:

 1. Keep it Concise

There’s no perfect length for a subject line, but shorter is usually always better. And since 53 percent of people open their emails on a mobile device, a lengthy line may get cut off anyway.

 A subject line should hint at what’s inside, but shouldn’t try to explain the entire email. A recent email that caught my attention was from Etsy with a short & sweet subject line:

“Oh, baby!”

Inside was a feature on different gifts for babies. The subject line managed to convey the general idea of what was inside and get me to click with two simple words.


2. Use a Casual Tone

Throw away the business speak now — even if you’re sending an automated transactional email. I recently subscribed to LinkedIn Premium. Instead of the basic “Your order is confirmed” this is the email I received:

“Welcome to Premium, Emma! Let’s get started.”

My eye also went straight to the email because it used my name. Setting up your emails to automatically fill in your customer’s name is simple, but the impact goes a long way.

Our own names are supposed to be the brain’s favorite word anyway, so why not use it?



This probably goes without saying, but anything written in all caps sounds like spam. Also, in keeping with rule #2 above, keep it casual by using lowercase. Your subject line isn’t a headline, it’s the beginning of a conversation.

Check out the small but subtle difference using a subject line from Airbnb:

 “What To Know Before Your Trip”  


“What to know before your trip”

 If you do want to emphasize something, you can give yourself one exclamation point per email — as long as you feel it’s necessary. Any more than one “!” will also look like spam.


4. Know Your Audience

There are two main types of audiences for your emails: people who know you and people who don’t. If you’re sending emails to a lead list, or people that have signed up for your emails in one way or another  — you have more freedom in writing a clever subject line because they already know you.

Purchase lists, or people who don’t know you, need a little more information in the subject line. You do not need to put your business name in the subject line (that will show up in the sender field.) You should, however, include a keyword or two as to who you are.

If you’re a real estate company your keywords might be: “Real Estate,” “Home Buyer,” etc.


5. Use Preview Text

 After your subject line ends, the preview text should fill in the rest of the email line. It’s important to make sure you set custom preview text, otherwise, an inbox will just pull something from the email text — which can look odd or provide incorrect info. 

Here’s an email where custom preview text wasn’t used: (Sorry Women’s March)

“Women’s March banner with a logo of faces”

Here’s an email where the custom preview text provides relevant info:  

“We ran the numbers. Here are last week’s stats…”

Your customers will get the most info as to what's inside — and will be more likely to click! 

Now you’re ready to get out there and start writing. You’ll start learning quickly when you see which of your emails get higher open rates. Another way to learn quickly is to use A/B testing.

Still have questions? Get in touch with Takeaway for personal advice on how to step up your email game.