Grammar or improper uses of words, that bothers me. I can normally continue to read regardless but if it seems to be a problem throughout I stop reading, a few errors here and there happen. I should know, I write fics myself and goodness knows I had trouble before I found a beta.

I like narrative, not just all dialogue, it makes it harder to keep up with what is happening if all there is is the characters talking to each other. Plots that jump about too much are annoying, or they just seem poorly developed.

As to pairings, I haven't read much in the CM fandom lately, but I don't particualarly go for that much. I don't know why, maybe I need to read more of it lol. I prefer male/female personally, nothing wrong with slash it just isn't my cup of tea. I tend to like stuff that is revolving around a case I guess.