Writing a good email subject line

The subject line decides whether the rest gets read. A few rules do most of the work.

Keep it short

On a phone only the first few words are visible. Put the most important information at the front, not at the end.

Be concrete

"Your order ships tomorrow" works better than "News from us". A vague subject line costs more opens than any trick gains.

Do not promise falsely

A clickbait subject gives you one open and an unsubscribe. The spam reports that follow cost far more than the open was worth.

Use the preheader

The line that follows the subject in the inbox. Many people leave it empty and throw away a free second chance to explain what it is about.

Test on the outcome

Not on opens, which are no longer reliable, but on clicks and what follows them. That is the only figure that tells you something useful.