Email is still the highest-ROI marketing channel — but most people write terrible emails.

The problem isn't effort. It's using generic prompts that produce generic copy. I've spent the last year testing AI email prompts and these 9 are the ones that consistently outperform everything else.

Copy, paste, replace [brackets] , send.

1. The Curiosity Gap Subject Line

Most subject lines either give away too much or too little. The curiosity gap sits in the middle — specific enough to feel relevant, vague enough to demand a click.

Prompt:

Write 5 email subject lines for [product/topic] using the curiosity gap technique. Each should hint at a specific benefit or insight without revealing it fully. Avoid clickbait — the email must deliver on the promise. Target audience: [describe audience].

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Example output:

"Why your automation workflow keeps failing (it's not the tool)"

"The freelancer mistake that costs €300/month on average"

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