Briefly. Because I'm still in winter blues recovery mode, though the lamp is doing wonders.
Now, some stories write themselves. Some stories simply appear on their own in the middle of me trying to do something else entirely. Those are wonderful. They are also rare and I have yet to find any connection between them.
Other stories are amenable to being written: it may be slowish going, but that's my fault, not the story's. When I'm able to get myself to sit down and write, these stories generally unfold themselves in an orderly fashion. We both know where we're going and roughly how to get there, and aside from a few tweaks here and there, not much revision is needed. It's a little easier to see what goes into making this sort of story happen: a) I have a handle on the POV's character voice. b) I've thought through the story and settling thoroughly enough that I'm not having to come up with answers to questions every other sentence. c) The scope of the story and the thematic core are pretty well established, so that I have a pretty good sense of what's needed where in order to make things work.
A good example of this kind of story is last summer's Respite. Yes, it took me a couple of years to write the thing from start to finish, but that's because I got completely sidetracked in the middle by the big MoL AU. It wasn't the story's fault, I just ... stopped writing it. Once I signed up for the gencestbang and had a commitment and timeline, I was able to bang the thing out in relatively short order. Finished a little closer to the deadline than I would've like, but it wasn't a scramble.
Freestyle, on the other hand, was a complete mess, because I didn't know what story I was trying to tell. It drifted through multiple POVs before I finally settled on John's; it went through different narrative styles, different tones, different themes, and was generally akin to picking up Jello with a dessert fork. And that's largely due to how it started: not with a complete story that I wanted to tell, but with the question/prompt: how did Sam and Dean learn swim in the MoL universe? They're both competent enough to rescue Lucas in the Evil that Walks Invisible version of "Dead in the Water", so they must have learned somehow, but they grew up in the middle of nothing but cornfields and the occasional shallow cow pond.
And in the end, that really is what the story wound up being about: John deciding he'd better teach his kids just in case, and how they react differently to that instruction--and then the reminder that John has no interest in it being more than emergency training, same as teaching them CPR or how to exorcise a demon. But it took me a heck of a long time to settle in on that, because I kept thinking it needed to be about something bigger, like John's ongoing frustration with the MoL and how they curtailed his search for Mary's killer even while giving him the resources needed to hunt the thing down. Or maybe the crushing of Dean's spirit into the good little yes man that we meet at the beginning of ETWI. Or John placing unreasonable expectations on his sons--etc.
In the end, what allowed me to finally write the dang thing was reaching the understanding that it didn't need to be anything more than a little vignette of MoL John teaching his sons to swim. Don't ask me why it took so long and so many extra words to get to that obvious conclusion--I just over-complicate things sometimes, I guess.
TL;DR - Light therapy lamps are amazing, you should totally buy one if you can't get yourself to do stuff during winter.