This may be a silly idea, but I though it might be fun and even of some use to collect some of the wisdom that the forum members have developed on the topic from the title. I'm looking not for concrete advice ("play this like that"), but for general principles. Much of this experienced players undoubtedly do almost subconsciously, but maybe with some reflection it can be brought to the form of explicit bits of advice anyway.
Fingering is obviously very important, and I don't think it can be learned from books, or at least that book hasn't been written yet. It is an art because various desirable goals often contradict each other, and everything depends on context.
I'll start myself perhaps, not because I think the following are indispensable pearls of wisdom, but just to illustrate what kind of thing I had in mind. To keep it simple, I'll just try to hit the right key at the right time (no considerations about legato playing for example).
(1) Get the job done in the most direct and simple way possible. Example: CDEFG could be played 12121, but 12345 seems preferable most of the time. For a slightly less silly example, 222222 rather than 123123 for CCCCCC works fine in slow to moderate tempo and saves mental energy. (The principle sounds trivial in this form, but I think for example Palmer-Hughes are guilty of a large number of transgressions.)
(2) Thumb on black keys is usually awkward.
(3) Avoid unnecessary risk. Larger intervals are safer when the thumb plays one of the notes. Example: CDEE' would be best played using the thumb on the E.
(4) The thumb is not the only finger that can be passed in chromatic scale like passages. Example: CDEFF#G can be played 123434.
(5) Related: Passing the thumb past 4 or 5 is awkward.
The question is actually perhaps more interesting for the CBA. I have three different methods books, and even on such a basic topic as scales, the three suggested fingerings have almost nothing in common.