I used to fly by the seat of my pants, which is why I have so many WIPs, some of which contradict each other in various points from righting out of order.

For longer fics, I'm trying to at least go into everything with a general outline these days. Leaves plenty of room for adjustments, but still has the plot in place.

For exchange fics, I get a general idea of where I want to go and then start writing.