A subject line works like a headline. Curiosity, a personal tone and a specific detail tend to win. Short and plain often beats clever.
The preview text right after it is a second chance to earn the open.
Do it step by step
- Write it like a message from a friend.
- Use curiosity: Did something happen?
- Use specifics: The 3 pages that sold 40k.
- Avoid spammy words and all caps.