This involves three skills: first recognizing a problem as a difficult one, then figuring out what heuristic you might have used, and finally coming up with a better solution.

Figuring out the particular heuristic seems more interesting than useful - "don't trust immediate answers" is a good rule, but it seems easier to start again than to de-bias an immediate guess (i.e. look up average salaries instead of trying to figure out how much you need to discount your guess of doctors' average salaries.)