Most people obsess over subject lines.

Most people obsess over subject lines.

But here’s the truth…

Your preview text is often doing more damage than your subject line.

Back when I ran MailNinja, I’d spend hours A/B testing headlines…

But totally ignore the preview line.

Until one day I realised:

→ My subject line was 🔥
→ But my preview text said “Can’t see this email? Click here.” 😬

That little line was tanking my open rates.

So I flipped the script.

I started writing preview text first.

And open rates jumped by 10–20% overnight.

Here’s my system 👇

→ Write preview text as a cliffhanger: make people curious
→ Make sure it complements — not repeats — the subject line
→ Check how it looks in Gmail and mobile (preview snippet length matters)

Now I teach this as part of my Email Essentials course inside GrowthKit.

Most founders think subject lines are the secret to high open rates.

Nah.

It’s the subject line + preview text combo that wins the inbox war.

Test it this week and let me know how it goes.

I killed off half my business.

In 2012, I made a terrifying decision.

I killed off half my business.

We were doing ok — websites, logos, a bit of everything.

But I knew if I wanted to grow, I had to specialise.

So I went all-in on one thing: email marketing.

No more generalist fluff. Just Mailchimp, email strategy, and inbox results.

The result?

→ Got listed on Mailchimp’s Expert Directory in 2013
→ Invited to Mailchimp HQ in 2019
→ Became their #1 global partner by 2020
→ Scaled my agency to $60k MRR
→ Built GrowthKit off the back of it

The takeaway?

Focus isn’t limiting. It’s liberating.

You don’t need more skills.
You need sharper edges.

Pick one thing. Own it. Build systems around it.
That’s how you scale without the chaos.

I teach this inside GrowthKit — starting with defining your 10x customer and niching down properly.

Don’t try to be everything.
Be the best at one thing.

Email did it for me.
What’s yours?

Content Library System™

Some founders are stuck in content panic mode.

Scrambling every week to figure out what to post.
Chasing trends instead of building systems.
Forgetting that good ideas compound… if you actually save them.

here’s the fix:

Build a Content Library System™

Inside GrowthKit, I show founders how to build a vault of ideas, so they never start from zero again.

→ I use a Notion database
→ Each idea is tagged by theme, channel, and format
→ I pull from 250+ Loom videos, transcripts, and swipe files
→ Then batch content and schedule it through Kit + Skool

Now, every post I write starts from a spark — not a blank page.

i call this the “save then scale” method

If you’re creating content weekly and not saving it?
You’re leaking leverage 🚰

Start a content library today
Future-you will thank you 😊

© GrowthKit, Doug Dennison and MailNinja 2005-2025 – All Rights Reserved

MailNinja ® is a registered trademark

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