When I write fanfic, I completely think of myself as shooting and then editing a movie--I kind of keep re-running scenes until they look right and, even more importantly, until the characters sound right. One thing I learned in B7 was just how little description it takes to set a scene, even if it's not in a canon location. However, even though I really like "sight gags" in stories it's hard to set them up well.

Personally I think that fanfic tends to unflesh DB--there's a lot of him to love as the seasons go on. And fanfic versions are almost always taller than the actors who play their canon characters.