Listen up and I'll tell you some "don't do this" and "look out for these tropes" I've absorbed from my adventures in writing. Some are my own invention, some are from college professors, and some are from the glorious Ebert:
The Traveling Sloth - Brainless characters are dragged along a wild adventure in which they do nothing and learn nothing.
Evangellion Effect - Huge world-changing events are happening but the characters are too obsessed with their personal problems to notice
Snow White - A character who does not act but inspires others to act for him/her.
Phantom Menace Challenge: Ask yourself and others if they can describe the characters in a story without mentioning what they look like or what their jobs are. The more the character can be described, the better written it is. Invented by RedLetterMedia.
Lots-O-Plots - A story with a main theme that strings many, many vaguely related characters together. There is no central character and too many people to pay attention to for a satisfying narrative.
Charles Dickens Dichotomy - The lead characters are impossibly bland and the side characters are impossibly interesting/loud.
Pride and Prejudice Plot - the plot hinges on a misunderstanding rather than an actual conflict.
Chosen One Syndrome - A classic example of self-insert writing in which an Average Joe(tm) turns out to be a hidden Messiah without any hard work. This is what sad lonely kids write when they wish a magical being would take them out of their miserable lives, but he never does. He never does (This sometimes works out great if you handle it just right).
Onesa Characters - All you need to know about the characters can be explained thusly: "One's a cop, one's a redneck, one's a woman, one's an Asian, one's a nuclear reactor engineer...." Invented by Ebert.
Mary Sue - A beautiful, brilliant, perfect self-insert character who is always right and everyone who disagrees will change their minds eventually. Closely related to the Chosen One trope
Childish Heroes - The protagonists are innocent man-children and sexless women, whereas the antagonists are mature career men and the women are sexually confident.
Brotman's Law - If nothing has happened in the first quarter, nothing is going to happen.
Morality Play - There's a very clear moral to the story from the opening scene onward. The depth to which this is pounded into our heads defines the badness of the story.
Dare to be Different then Die - If the character struggles to be their own different self over the course of the story, then they are a success (Examples: Angus, Whale Rider). If the character is already brave to be themselves in the opening scene, they will be humiliated and die horribly, thus becoming martyrs against a cold unfeeling world (Examples: Boys Don't Cry, Million Dollar Baby).
Idiot Plot - A conflict that would be solves easily if all the characters were not idiots. From Ebert.
Woman in the Refrigerator - The female love interest/girlfriend/wife of the character serves no purpose except to die or be kidnapped, thus cementing the badness of the bad guy and the reason for the hero to do anything. This also frees the hero of anything to keep him from doing cool crazy dangerous stuff. Invented by Gail Simone.
Evil Trio - The smart man, the sexy woman, and the strong idiot man.
The Moses Story - A guy belonging to Group A enters Group B. Guy is confident in the greatness of A over B. After spending time with B he decides he likes B better and fights on B's side instead. As seen in The Bible.
Examples: Pocahontas, Avatar, The Last Samurai, Dances with Wolves, etc.
Odd Couple - Two people with little in common are teamed into a situation with wacky results.
Wandering Hero - A stranger enters a microcosm. He will be a famous hero in said microcosm by the story's end.
Sturgeon's Law - 90% of everything is crap. Remember this before falling in love with a first draft.
(Thank you Attenuasis for reminding me of this one)
The Bechdel Test - Stories pass the Bechdel Test if they contain more than one female characters who at some point have a conversation that is not about one of the male characters.
This also applies to the main characters - do the side characters have scenes and conversations that have nothing to do with the main? Invented by Alison Bechdel.