In sales, the biggest challenge isn't a "no”, it’s never being seen at all. To stay out of the "Promotions" tab and earn a click, your subject lines need to look like a one-on-one conversation, not a mass broadcast.
Use these two rules for writing email subject lines that actually get opened.
Rule 1: The 5-Word Maximum
Your subject line has one job: get the email opened. If it’s too long, it looks like a marketing newsletter and gets deleted before the prospect even reads your name. Keeping it under five words ensures the recipient can quickly read it, and that the entire message is visible on a mobile lock screen.
| ❌ Avoid (Too Long/Salesy) | ✅ Try (Under 5 Words) |
| "Increase your ROI with our new Reporting Dashboard" | "Question about [Company]’s goals" |
| "Checking in to see if you have time for a call" | "Ideas for [Project Name]" |
| "Helping [Company] scale your engineering team" | "Thoughts on [Topic]?" |
Rule 2: Prioritize Curiosity Over Pitching
The moment a subject line feels like a "pitch," the recipient’s brain shuts down. To get an open, you need to pique their interest without giving everything away in the header.
Note: Curiosity must be honest. If you have never spoken to the prospect, avoid "fake" familiarity (like re: our call). This feels like a bait-and-switch and leads to your email being marked as spam.
| ❌ Avoid (The "Clickbait" Trap) | ✅ Try (Honest Curiosity) |
| "re: our conversation" (If you haven't spoken) | "[Name] + [Your Company]" |
| "tried calling you" (If you didn't call) | "[Event Name] next week?" |
| "Final attempt to reach you" | "question regarding [Department]" |
| "Urgent: Open immediately" | "[Company] / [Your Company]" |
Expert Tip: Write like a human, not a brand. Using lowercase or sentence case (e.g., "question about the q3 goals") instead of Title Case makes the email feel like a personal note from a colleague rather than an automated blast.
Summary: The "3-5-0" Formula
Before you send your next email, run it through this quick mental filter:
- 3 Seconds: Does it spark curiosity in under 3 seconds?
- 5 Words: Is the subject line 5 words or fewer?
- 0 Pitches: Does it contain exactly zero "sales" words (like ROI, Discount, or Solution)?
Ready to improve your open rates?
Use Snippets for your "Curiosity Hooks." Snippets allow you to easily drop pre-written, high-performing text into your emails. Start building your library of high-performing subject lines by following this article: Create a Snippet.
We want to hear from you: Share your best-performing "Curiosity Hook" in the comments below!