How To Write An Email Subject Line

You can write the best email of your life and lose on the subject line. It is the only part most of your list will ever see.

And the ones that work are almost never the clever ones.

Specific beats clever

"Something big is coming" gets opened once. "We dropped our cost per lead to nineteen dollars" gets opened every time.

Specificity does two things. It tells the reader what they are getting, and it signals that there is something real inside. Vague curiosity works until people learn that your vague subject lines lead to nothing, and then it stops working permanently.

The test: could a competitor send this exact subject line? If yes, it is not specific enough.

Short wins, mostly because of phones

Most of your list reads on a phone, where somewhere around forty characters is visible before it cuts.

Which means the useful part goes at the front. "New case study: 1.2 million views in four months" works. "In this week's newsletter, a new case study about how we generated 1.2 million views" does not, because nobody sees past the first four words.

The ones that work

The number. "Six things I would do differently." "Twenty dollars a lead." Numbers are concrete and they stop the eye.

The plain statement of the thing. "How we write a proposal that closes." No dressing. Works because it reads like a person rather than a campaign.

The question the reader is already asking. "Why did your reach drop?" Works when it is genuinely their question, not yours.

The one word or two word subject. "Read this." "Quick one." Works occasionally and only because it is unusual. Use it twice a year, not twice a month.

The named thing. If you are writing about a specific project, client type or place, name it. "What we learned on a Bondi build" beats "lessons from a recent project".

The ones that do not

Fake urgency. "Last chance" when it is not. People remember.

Re: and Fwd: on a cold email. It gets opened and it burns the relationship in the first second.

All caps and three exclamation marks. Straight to promotions.

The clever pun that requires the email to explain it.

Anything that sounds like it came from a marketing department. If you would not text it to a friend, do not send it.

Preview text is the second half

Most people write the subject line and let the preview text default to the first line of the email, which is usually "Hi there" or an image alt tag.

That is free real estate. The preview should continue the subject line rather than repeat it. Subject: "We dropped cost per lead to nineteen dollars." Preview: "Here is the exact change we made to the creative." Together they do the work of a headline and a subhead.

Test one thing

Split the list, change only the subject line, and send the same email. Everything else stays identical.

Two sends tells you nothing. Ten tells you something. Thirty and you have a pattern worth writing down, and it goes in the swipe file described in how to build a swipe file you actually use.

And none of it matters if the email itself is not worth opening. Open rates that fall over time are usually a content problem, not a subject line problem, which is the whole of why your email list stopped opening. Get the email right first, the way how to write a newsletter people open sets out, then make the subject line earn the click.