Dear me, six months ago —
You are about to spend a significant amount of time being confidently wrong about things that matter enormously. This is not a warning. It is the job description. What separates the founders who build something durable from the ones who do not is not whether they are wrong — everyone is wrong, repeatedly, at every stage. It is what they do when the evidence shows them where.
I am writing this down now because there are things I wish someone had told me directly at the moment I was starting. Not the generic startup advice — you have read all of that. The specific things that I got wrong in ways I could have gotten less wrong if I had approached them differently from the beginning.
The thing you are most certain about is the thing most worth testing first
Right now you have a belief about your customer that feels so foundational it does not occur to you to question it. It is not a hypothesis — it is the ground you are building on. You are designing everything else around it.
I want to tell you that this specific belief is the one you most need to test, rigorously and early, before it gets embedded in your product design, your pricing model, your go-to-market strategy, and your fundraising narrative.
The beliefs that feel foundational are the ones that are hardest to update once they are wrong because so much else has been built on top of them. The earlier you test them, the less it costs you to update them. You will update them. The question is how much you will have spent before you do.
Do not wait until you have enough usage data. Go have five direct conversations with people who represent your core assumption this week. Be genuinely open to hearing something that contradicts what you believe. If what you hear mostly confirms the belief, good — you have earned the right to build on it. If it does not, you have saved yourself months.
The advice you will resist is usually the advice you need most
Somewhere in the next few weeks, someone — probably someone you respect and whose opinion you have sought — is going to tell you something about your business that makes you defensive. You are going to have two or three very good reasons why they are wrong. You are going to leave the conversation feeling more committed to your original position than you were when you arrived.
I am asking you to do something uncomfortable with that experience. Before you dismiss it, spend thirty minutes asking yourself why a thoughtful, well-intentioned person who understood your business reasonably well looked at what you are building and arrived at that conclusion.
They might still be wrong. But the instinct to defend is almost never the right first response to feedback from people who know enough to have an informed view. The defensiveness is often a signal that the feedback has hit something real — something you already know at some level but are not ready to examine yet.
The founders who update their thinking quickly do not have less conviction than the ones who do not. They just have better mechanisms for separating the feedback that is actually useful from the feedback that is not — and they learned those mechanisms by being genuinely curious about challenges to their thinking rather than reflexively resistant to them.
Slow down on the product, speed up on the customer
You are going to spend the next several months building things nobody explicitly asked for. Not all of them — some of what you build will turn out to be exactly right. But a meaningful fraction of your building time over the next six months will be spent on features and improvements that your assumptions told you were important but that your customers, if you had asked them directly, would not have prioritised.
The corrective is not to stop building. It is to make every significant building decision contingent on having spoken to someone who represents the target user in the last two weeks. Not a survey. A conversation. One conversation with a real person who has the problem your feature is meant to solve is worth more than a week of internal discussion about what that person probably needs.
For every hour you spend on feature development in the next six months, spend at least forty-five minutes in direct conversation with someone in your target customer segment. The product will be better. The roadmap will be shorter. The things you build will land harder because they will be built for a real person rather than a model of a person.
The numbers that matter are not the ones you are tracking
Right now your dashboard is full of acquisition metrics — signups, traffic, conversion rates from free to paid. These matter, and you should keep tracking them. But they are trailing indicators. By the time they tell you something is wrong, you are already several weeks into a pattern that is hard to reverse.
The leading indicators you should be tracking are qualitative and relational. How many founders have you spoken to this week who were not already users? Of the conversations you had, what fraction surfaced a belief about your product that was different from the belief you went in with? What is the ratio of conversations that confirmed your assumptions to conversations that challenged them? If it is high, you are selecting for confirming conversations, not genuinely learning ones.
Also: track the stories. Not the metrics — the stories. Keep a record of the specific moments when the product did what it was supposed to do for a real person. These stories are the evidence that the thing is real. You will need them on the weeks when the metrics are not moving and your conviction needs something more concrete than a spreadsheet to rest on.
You are going to be okay
Not every week. There will be weeks that feel genuinely hard — where the progress seems impossibly slow, where the people you respect ask questions you cannot answer well, where the gap between where you are and where you need to be feels uncomfortably large.
Those weeks are part of it. Not the exception — the rhythm. The founders who build things worth building are not the ones who avoid those weeks. They are the ones who have developed enough relationship with their own doubt to keep working through it without either collapsing into it or suppressing it.
You have the capability for this. I know because I am the version of you who got through the first six months. The stubbornness that sometimes makes this harder than it needs to be is also the thing that makes it possible.
Keep going. Do the interviews. Listen to the challenging feedback. Build for the real person, not the model of the person. The rest follows from those three things more reliably than from anything else I have found.
— You, from six months later