I mostly upvote replies, and sometimes Meditations, but not many questions. I will upvote any reply that I think is informative, well-written, and correct.

I downvote rude posts. I will sometimes downvote RTFM replies that are phrased rudely, even where an RTFM is appropriate. I also downvote replies that present themselves as authoritative but contain glaring mistakes that don't appear accidental.