Product discovery & market research
I start with the problem: who has it, how often it appears, how people solve it today, and why the current solution is not good enough. I use interviews, competitor research, behavioral signals, and market context to separate interesting ideas from problems worth building for.
For early-stage products, I also think about viability: who the customer is, how the product can reach them, what they may pay for, and whether the product has a realistic path to adoption.