1. Conduct customer development interviews where you interview potential users and don't show them your product. Simply ask questions that will demonstrate to you if they have pain.
2. For each pain statement, ask them to rank it's importance on a scale of 1 to 10 and their satisfaction with their current solution on a scale of 1 to 10. This helps you quantify the size of the opportunity.
2.a. repeat this process 50 to 200 times.
3. Stock rank your pain statements based on the largest surface area.
4. Build an MVP.
5. Show it to the people that rated the pains the highest and ask for feedback.
6. If you really nailed it they will be asking you how they can become customers.
7. If they're not asking how they can buy then ask for more feedback.
I think the quantify step was pulled from "lean product management".
I've followed this twice and you usually have to loop through the feedback step a few times before you get it.
Both times, my first 10 customers have come from these interviews and my next 100 have come from referrals from those initial 10. I think that's the gist of Ash's 10x product launch.
I'm being fairly brief because it's a complex subject and I'm on mobile.