At this point in my reading life what grabs me seems to be a character or characters that I'd like to spend some time with, plus a situation that seems at least moderately interesting. The character doesn't have to be "nice" but they need to not be a jerk. Because I invest in the characters, I also dislike prologues that set the stage from x years ago, or mysteries that open with a viewpoint character who is about to be murdered, or suspense that spends more than a very little time in the villain's head as they are planning their next nefarious step. Not a hard-and-fast rule, of course - there are good books that do all those things, for good reasons - but at this point they're just not what I want to read.

I used to be a sucker for particular plot or plot/character tropes, but that seems to have become less true; there have been too many books that sound like something I expect to like but then I don't.