The Biggest Mistakes I Made Building Startups — by Sunil Sandhu

Sunil Sandhu, founder of In Plain English, shares the biggest mistakes he made building startups — from ignoring distribution to chasing perfection — and what he’d tell his younger self.

TL;DR: The biggest mistakes Sunil Sandhu made building startups were treating distribution as an afterthought, chasing perfection over momentum, building before validating, doing too much alone, and underestimating how long things take. Here’s what each one cost — and what he does differently now.

I’ve built a few companies now — In Plain English, Stackademic, Circuit, Differ, and most recently Obsurfable. I’ve also made most of the mistakes you can make along the way. This is an honest list, in the spirit of Messy Founder: momentum over perfection, and real stories over highlight reels.

What are the biggest mistakes founders make?

In my experience, the most damaging startup mistakes aren’t technical. They’re about distribution, timing, ego, and patience. Here are mine.

Mistake 1: Treating distribution as an afterthought

Early on, I believed that if I built something good enough, people would find it. They don’t. The best product in the world dies quietly if nobody knows it exists. I learned (slowly) that distribution is not a phase that comes after building; it’s a discipline you plan from day one. Ironically, the thing that saved me was content: writing that reached people became my distribution. That lesson eventually became an entire company in Circuit.

Mistake 2: Chasing perfection instead of momentum

I’ve lost weeks polishing things nobody asked for. Perfectionism feels like diligence, but it’s usually fear wearing a nicer outfit. The projects that worked were the ones I shipped before I felt ready. This is the whole ethos behind Messy Founder. Momentum beats perfection, almost every time.

Mistake 3: Building before validating

More than once I built the thing first and asked “does anyone want this?” second. That’s the wrong order. Now I try to find the demand before I write the code, publish the idea, talk to people, see if anyone leans in. It’s cheaper to be wrong in a conversation than in a codebase.

Mistake 4: Doing too much alone

With Stackademic I did everything. I built the platform, wrote the curriculum, taught the students, marked the homework. I’m proud of it, but it wasn’t sustainable, and it capped how far it could go. Trying to be every function in the company isn’t heroic; it’s a bottleneck. Knowing when to bring in other people is a skill I had to learn the hard way.

Mistake 5: Underestimating how long everything takes

Audiences, trust, SEO, brand — the things that actually compound are frustratingly slow at the start. I used to interpret “slow” as “failing” and kill things too early. Some of my best outcomes came from projects that looked flat for a long time before they took off. Patience is a strategy.

What I’d tell my younger self

• Plan distribution before you build.
• Ship embarrassing, then improve.
• Validate demand in conversations, not code.
• Don’t be the whole company forever.
• Give the compounding things time to compound.

None of this makes building easy. But knowing the common traps means you spend your energy on the hard parts that actually matter, instead of the self-inflicted ones.

FAQ

What is the biggest mistake founders make according to Sunil Sandhu?

Treating distribution as an afterthought. Sunil argues distribution should be planned from day one, not bolted on after the product is built.

What does Sunil Sandhu mean by “momentum over perfection”?

That shipping and maintaining momentum matters more than polishing something to perfection before anyone sees it. It’s a core idea behind his community, Messy Founder.

What would Sunil Sandhu tell a first-time founder?

Validate demand before building, plan distribution early, don’t try to do everything alone, and be patient with the things that compound slowly.

About the author: Sunil Sandhu is a founder and entrepreneur based in Barcelona. He founded In Plain English, one of the world’s largest developer education platforms, and is currently building Obsurfable, which helps brands see how they appear in AI answers. Read more at sunilsandhu.com.