The best email in the world achieves nothing if it isn't opened. Your subject line decides that in a split second. Good subject lines aren't about tricks. They're about being clear, relevant and a little bit interesting.

Be specific

"Newsletter #42" gives nobody a reason to open. "3 quick ways to cut your energy bill this winter" does. Tell readers what they'll get.

Keep it short

Many people read email on a phone, where long subject lines get cut off. Aim to put the important words at the start and keep the whole line brief.

Use the preview text

The preview text appears next to or beneath your subject line in most inboxes. Use it to add detail or curiosity rather than letting it default to "View this email in your browser".

Approaches that work

• Benefit: "Get your weekends back with this simple booking setup"

• Question: "Is your website losing you enquiries?"

• How-to: "How to price your services with confidence"

• Number: "5 tools I'd recommend to any new business"

• Timely: "Last chance: workshop places close Friday"

What to avoid

• Misleading subject lines that don't match the email

• ALL CAPS and lots of exclamation marks

• Fake "Re:" or "Fwd:" prefixes

• Overused spam-trigger phrases such as "100% free" or "act now"

Test and learn

Most email platforms let you A/B test two subject lines on a small part of your list and send the winner to everyone else. Over time you'll learn what your audience responds to.

A simple rule: if you wouldn't open it yourself, don't send it.

The short version

Be specific, keep it short, use the preview text and test regularly. Pair good subject lines with good deliverability habits to reach the inbox in the first place.