I've been reading a lot of posts about outlines over at Crimson League and it's got me thinking about how I use outlines when writing A Mage's Power. Most of the time I don't use them. I just think about what the characters involved would do next and follow that. When I get stuck or lost I use an outline I call the Character Action List (CAL) .
I create a list of events: '1. Bob does x. 2. Alice does y. 3. Charles does z. 4'. etc and I flesh out those actions when I do the true writing. One point can spiral out into several paragraphs because it is a general idea. It expands like unpacking a suitcase. This is enough to get the ball rolling and move on to the next scene.
This practice of CAL flows out of the idea that stories should be driven by their characters instead of their plots. A plot is nothing more than characters interacting with each other and their world; creating a list of the actions characters take in that world can do wonders for writer's block. When it comes time to write you have something to hold onto and push from. It also serves as a check against Idiot Balls.
If the plot demands something of a character then a plot outline can hide how out-of-character it could be. The Character Action List reveals the sequence of actions taken by the character and so it isolates the weak link where the character behaves differently than normal. Spotting this sort of thing is the difference between leaving a reader in awe and providing them with snark bait.
Don't forget that the CAL is a short term thing. It maps a small area that you're stuck in and no more. Bigger outlines don't take organic growth into account and so they are too limiting. The characters are ignored in favor of what the author wants to do. Use the CAL to listen to them and your story will be better for it.