Improving open rates with a creative subject line

These are the three things that have the most effect on the open rate of any email.

1. Personal relation between receiver and sender.
2. Placement of the email in receiver's inbox.
3. Headline/Subject of the email.

Subject line formulas

1. How/Where to Find {Desired Output} Even When It's Impossible
   Example: How to Find {Peace} Even When It's Impossible

2. How To Make {Desired Output} That Matter to {Authority}
   Example: Make {a SaaS} That Matter to {Venture Capitalists}

3. How {Authority} Got {Result} In {Timeframe} Using {Solution/Product}
   Example: How {Spotify} Got {500K Users} In {10 Days} Using {Twitter Ads}

4. {n} Ideas You Can Steal From {Authority}
   Example: {101} Ideas You Can Steal From {Experienced Copywriters}

5. {n} Secret Tools Used by {Authority}
   Example: {11} Secret Tools Used by {Successful Investors}

6. Why {Authority} Don't Use {Competitor}
   Example: Why {Big Publications} Don't Use {Google Analytics}

The article is a bit long but dives into how to construct newsletter subject lines that improve open rates.

https://newslettercrew.com/improving-open-rates-with-a-creative-subject-line/