Here are a couple I forgot to include when I posted in this thread in January:
1. I hate when a character's eye color, hair color or some other pointless feature that the author is far too enamored of gets mentioned in every scene. It's not that you can only mention those features once in the novel (twice might be OK, maybe, if it's a romance, I guess), just don't have his gray eyes flashing and her blond hair shimmering every time that character comes into a scene. These are not even good character details, they're generic.
Think about the last person you interacted with. Were you really thinking about hair and eye color? Or were you thinking about what they actually said, or wondering why they hadn't bothered to shower this morning? My boss came in and handed me an article I was looking for, and I wondered why on earth the magazine he handed me was warm. That weird detail stood out far more than his eye color, which I suppose I see so often that I never bother to think about it.
2. I hate when authors fawn over their characters by writing their names over and over like a middle schooler scribbling the name of a crush on the cover of a notebook. I read a book where the main character was a Marysue named Baby Hunnicutt (crikey, I know) and it was Baby this and Baby that in every single line and everyone who spoke to her said "Baby, bla bla bla bla bla bla dee bla bla, Baby," and when the author got inured to that she started having the characters make up saccharine nicknames for the Marysue like "Sweet Baby Blondie-locks." *searches in vain for vomiting emoticon*
By halfway through that book I was thinking about writing a fanfic where Baby is stalked by a gum chewing serial killer.
Wait, what were we talking about?