I'm v lazy with fanfic, and I never outline. Things kind of crop up on me, like there was a whole 'corpse in the shrubbery' moment in something recently - and who knows where that came from? It worked, I think, and it was absolutely last minute.
With proper stuff, though - I have to outline. We outline to death, and half the dialogue goes in there so really you're writing the actual thing, not just a plan.
This is no help at all, is it?