Tag: motivates your characters
You can listen to your cast of characters at any stage in the writing process, but it might be especially useful near the end when most of the story is fleshed out. It can be a good check of your story logic and add a last ingenious layer of polish.
When writing your next villain, give him or her as detailed a backstory as your protagonist. TV's Buffy and Firefly provide some great examples of well-developed, three-dimensional villains to use as inspiration.
Power moments in your story set up life-changing events and propel your story forward. Writing great dialogue often depends on the subtext you create in setting up these moments.
One way to envelop your reader in a new world is to create (or appropriate) slang. Done clumsily, it can detract from your story, but Buffy and Firefly show how slang can add nuance to your story's universe.