Let's Make It Open - Killer Tips For Email Subject Lines For High  Open Rates

Let's Make It Open - Killer Tips For Email Subject Lines For High Open Rates

What I’ve learned writing and editing 800+ email subject lines while running email campaigns for various niches.

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Daniel Kebbe
·Jul 1, 2021·

2 min read

One key to high open rates?

Write killer subject lines.

1/ Experiment often.

We A/B test 4 different subject lines every day.

We study what works/doesn’t work and make adjustments constantly.

2/ Shorter is (almost always) better.

Here’s a list of winning subject lines from our most opened emails over the past ~10 months.

3/ Shorter, please!

Our top 20 best subject lines averaged 33 characters.

The bottom 20 averaged 41 characters.

4/ Boring isn’t always bad.

Here’s the subject line from our most clicked email, which had a 55% open rate:

“How bitcoin are created”


These 3 subject lines all made our Top 20:

“How a tiny D2C company hacked its way to $500k/mo in sales”

“Why NFTs are suddenly selling for millions of dollars”

“We interviewed 20+ vending machine owners. Here's how much they make.”

6/ Assertions are better than questions.

Assertion: 🏦 Stripe Treasury is a huge deal (51% open rate)

Question: 💸 Will Big Tech lose its tax shelters? (42%)

7/ Solutions (and numbers) sell.

📧 Fixing the $650B subscription economy (46% open rate)

🎯 How Target took $9B from competitors (46%)

She was kidnapped and locked in a car trunk. Then, she decided to change the car industry. (47%)

8/ Kinda obvs, but news also sells.

Amazon’s next play 🚚 (53% open rate)

Apple fires Intel (52%)

📦 Jeff Bezos is stepping down (51%)

🍟 McDonald’s is crushing it (51%)

🙅‍♂️ Zucked (51%)

9/ Question assumptions.

As a journalist, I've always assumed that conflict sells.

That’s not always true.

💸 Will Big Tech lose its tax shelters? (#244 most opened email since Aug. 2020)

🍭 Big Candy vs. Cannabis (#182)

💻 The Google Docs pickle (#101)

10/ Another assumption: People love explainers.

We wrote at least a dozen subject lines with some variation of “X, explained”

Not one cracked the Top 50.

11/ What not to copy.

Our email with the lowest open rate had this subject line:

“Board games are starting to look a lot like video games”

I don’t even know what that means...and a sh*t ton of readers didn’t care either.

12/ In sum, to write great subject lines:

  • Experiment often
  • Keep it short
  • Keep it simple
  • Help people make $$
  • Assertions > questions
  • News sells
  • So do solutions
  • Conflict is overrated
  • So are explainers
  • Don’t make people think too hard

13/ If you like breakdowns like these: Please rate & like my post :)

I write about email growth tactics with the occasional wisecrack.

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