7 subject line tactics that lift your open rate

Your subject line is the first thing subscribers see in the inbox. Here are seven tactics that move the open rate in a measurable way:

1. Keep it short: under 40 characters fits fully on mobile.
2. Personalize it: campaigns that use the {{first_name}} tag see a clear lift in opens.
3. Spark curiosity without stooping to clickbait.
4. Use numbers: concrete promises work.
5. Add urgency — without overdoing it.
6. Try an emoji: if it suits your industry, it helps you stand out.
7. Run an A/B test: listen to the data, not your assumptions.

Qulaq's reports show you which subject line won at a glance.