So here's my last-minute post on dialogue. (Sorry this post is so late. I ran my first half marathon this morning!)
The First Novels Club has my favorite article on dialogue. They analize each part of dialogue, give a tip, and then show by example. Good stuff.
Next, some oldies but goodies:
Some people go overboard with dialogue. Author2Author lists a few things to be aware of when writing dialogue. One big thing to remember: Dialogue slows pacing!
A while back I posted on the Functions of Dialogue. While this post from The Blood-Red Pencil is similar, I love the fresh perspective. It's worth a quick read.
And a few tips from yours truly:
To use dialogue to create conflict, you can list what each character in the scene wants and try to find two things that don't match up. For example, Penny wants to wear red, but her husband wants her to wear black.
This can also help you throw in some conflict. For example, maybe Penny's red dress is dirty and the black dress isn't warm enough for the weather. Suddenly, the two of them are scrambling to make their preferred color dress wearable. (Penny throws her red dress in the wash, while her husband looks for a black shawl to put over the backless dress.)
Remeber to use dialogue to show conflict. If the dialogue isn't related to the main conflict in the scene, it doesn't need to be in there! Dialogue always moves the story forward!