This was a tough one, too, as I had the merest whisper of an idea when I started:
A guy is driving, and stops at a roadside place.
Something weird happens.
That was it. So I began.
"Guy had been on the road for days, and felt crumbled around the edges. Running away wasn't easy, because at some point, you had to stop, and the horrors that you were running from had time to catch up."
Pretty good, I thought. So I commenced to laying it down, line-by-line, until it began to have a shape. And I kept adding bits that came along, and the shape resembled a storyline. After a long while, I had the end in sight, and was able to bring everything together. Usually, I have much more of an idea of where a story is going.
So it's good, and one of my longer short stories, at 5000 words. Off it went for the first submission, all raw and bleeding. But first there was fixing the maddening format issues. (Anyone hate the new version of Word as much as I do?)
So many things came up as blockers, I was getting the idea that Fate was trying to prevent the story from being finished. But being a working writer is refusing to accept defeat, and I ground my teeth, lowered my head, and kept at it, until it was off and well submitted. Damn tough slog, but I have another good work in the queue. And that's what it's all about.