15 APR 2026
6 MIN READ
Your subject line is the only job of your email until someone opens it. Everything else is irrelevant if this one line doesn't land. Here's what actually works.
until someone opens it. Everything else is irrelevant if this one line doesn't land. Here's what actually works.1. SHORT AND SPECIFIC BEATS CLEVER
Subject lines under 50 characters consistently outperform longer ones. Specificity builds trust vague, mysterious lines feel like spam. Tell the reader exactly what's inside and make it feel worth their time.
- Aim for 3050 characters for best mobile display
- Lead with the most compelling word
- Avoid filler phrases like "Don't miss this"
- Numbers consistently boost open rates
2. CURIOSITY DONE RIGHT
Curiosity gaps work when they're honest. Tease something real that's inside the email not a manufactured mystery. "What we learned from sending 10,000 emails" is curious and credible. "You won't believe this" is neither.
3. PERSONALISATION STILL WORKS
First-name personalisation in subject lines can lift open rates but only if the rest of the email delivers on it. Segment your list and tailor subject lines to the recipient's context, interests or stage in the customer journey. Relevant beats clever every time.
The best subject line is the one that makes your reader think "that's for me."
4. TEST EVERYTHING
A/B test your subject lines on every send if your list is large enough. Test one variable at a time length, tone, question vs statement, emoji vs plain. Over time, you'll build a data-backed picture of exactly what resonates with your specific audience.
5. WHAT TO AVOID
Avoid all caps, excessive exclamation marks, spam trigger words like "free" or "guaranteed", and misleading subject lines. Beyond hurting deliverability, they destroy trust. Once a subscriber feels misled, they'll either unsubscribe or mentally check out and you'll never win them back.
Want an email strategy that drives real engagement and revenue? Let's talk.