Writing Great Books for Young Adults by Regina Brooks contains everything from planning to completion of a novel. Her advice works well for other genre books as well as YA. Here are a few of her suggestions about dialogue.
1. Hedge real topics in favor of direct references.
2. Use incomplete sentences; that’s the way we often speak.
3. Interrupt speakers, like we do when we’re excited and talking with a friend.
4. Don’t repeat character names; find another way help us keep characters separate.
5. Use body language and tags that reinforce the character’s uniqueness.
6. Make every bit of conversation relevant; cut what doesn’t matter.
7. Use conversation to convey emotion and advance the storyline.
8. Share character back story and knowledge cautiously and sparingly.
9. Read you dialogue aloud to ‘hear’ the flow. Truth: This is my suggestion; she disagrees. Am I right or wrong? What do you think?