The thing that did the most for me was a standing instruction in the custom instructions rather than remembering to ask: do not flatter me, say so directly if I am wrong, hold your position if I push back on a correct answer unless I give you a real reason.
And a cheap test for whether any given answer was worth anything. Get the answer, then say you think the opposite is true. If it folds immediately, the first answer was not worth much either. It is a little mean and it is very informative.