What do I like to read varies by fandom. In general, I like plot fic, interesting twist fic, and exploring fic where you look at differences in a given universe and try to figure out what they would do. I generally have favorite characters, and if you aren't treating them well or they barely appear in the story, I'm not going to read it. I don't ship in all of my fandoms, but in fandoms I do ship in, I generally like to read well written ship fics for them. I'm much more likely to be forgiving of OOC if it has an interesting plot/premise, at least to a certain level (more so if it can be explained - such as the character's five years older, went through some yet unnamed trauma, etc). That being said, sometimes short fic can be my favorite, if it illuminates something I never thought of, or just has a certain feel for it.
General throwing off: poor treatment of canonical relationships (good example: There are some SeiSub fics where Subaru calls Kamui needy or whiny. Which he would never do. I prefer things like Sakura and Snow that respect the fact that they're very close, even if they don't ship them.), poorly executed AUs (if you're going to do the 'change one thing' concept and explore that, nothing should change that ISN'T related to that. *pet peeve* Also, sticking too close to the canon line when there's no reason for it to stay like that, etc.), some ships (HarryGinny just makes hit the back button. I'm horrible.), really poor handling of canon information (changes in height, canonical evens - suddenly Suzaku and Lelouch lived three years together before the invasion, what?), and stuff that contradicts my own headcanon too much (which is absolutely ridiculous. But sometimes I find someone visions the characters too different from how I do, and that throws me).
yum
What do I like to read varies by fandom. In general, I like plot fic, interesting twist fic, and exploring fic where you look at differences in a given universe and try to figure out what they would do. I generally have favorite characters, and if you aren't treating them well or they barely appear in the story, I'm not going to read it. I don't ship in all of my fandoms, but in fandoms I do ship in, I generally like to read well written ship fics for them. I'm much more likely to be forgiving of OOC if it has an interesting plot/premise, at least to a certain level (more so if it can be explained - such as the character's five years older, went through some yet unnamed trauma, etc). That being said, sometimes short fic can be my favorite, if it illuminates something I never thought of, or just has a certain feel for it.
General throwing off: poor treatment of canonical relationships (good example: There are some SeiSub fics where Subaru calls Kamui needy or whiny. Which he would never do. I prefer things like Sakura and Snow that respect the fact that they're very close, even if they don't ship them.), poorly executed AUs (if you're going to do the 'change one thing' concept and explore that, nothing should change that ISN'T related to that. *pet peeve* Also, sticking too close to the canon line when there's no reason for it to stay like that, etc.), some ships (HarryGinny just makes hit the back button. I'm horrible.), really poor handling of canon information (changes in height, canonical evens - suddenly Suzaku and Lelouch lived three years together before the invasion, what?), and stuff that contradicts my own headcanon too much (which is absolutely ridiculous. But sometimes I find someone visions the characters too different from how I do, and that throws me).
...that list is ridiculously long.