Hahaha, well, mostly mine is the coasting along while chewing on interesting tidbits thing? If it's a longer story (by which I mean like 1-3K), I'll pick out a general sequence of events and connect the dots, not necessarily in order- I tend to shuffle scenes a lot to see how I like the look of things. If it's shorter, I'll usually just transfer one central idea/theme/scene from brain to page and then build around that as I find it necessary.

Depending on whether I have a prompt or not (I prompt myself a lot of times, since it seems to help), and whether or not it's for some sort of challenge/exchange (deadlines often trigger something deathly to my writing-think), the whole process could either go really smoothly and without brain or, you know, in fits and starts and headdesks and mental agony. :P