[daveydave]

Breaking a problem down into smaller problems, solving those that are immediately obvious or known from experience, for harder or new problems: gathering evidence if available, coming up with a hypothesis, testing this against the available evidence, looking for reasons why the hypothesis must be wrong and abandoning it if reasons are found, iterating on the hypothesis until an adequate one is found (adequate being provably correct, or "sounding sensible" based on solutions to similar problems). My 2c is being ok with uncertainty and being wrong, and an awareness of cognitive biases can be helpful.