I try to avoid the Writing for Noobs arena and focus on Becoming a Decent Writer – often writing about writing is ironically dreadful, but I do admit to sharing Craig Clevenger’s pet peeves:
TALKING HEADS, HEARING VOICES AND THE DISAPPEARING NARRATOR
I have two major pet peeves when it comes to dialogue. First, it bugs me when all the characters sound alike. Sure, with regional diction, accents, socioeconomic class, blah blah blah, it may be tough to distinguish between the Valley Dude speak of two high school kids, but not between those kids and their teachers or parents. Secondly, when characters speak with the same eloquence, or at very least the same style, as the narrator, i.e., the author, it rings false for me. One of the most valuable classes I had as an undergrad was a single semester of writing for the stage, during which we wrote two one-act plays. I still intended to write prose fiction, but writing plays forced me to hang the story on characters and dialogue.