There's a couple of answers to this. I'm talking now purely about my internal processes, not techniques or approaches which I think could or should be replicated by other writers. So take this post with a peck or two of salt -- if they help, great. If not, feel free to point and laugh.
specficrider once said I don't write stories so much as channel them. This is certainly what it looks like from the outside, and from the inside as I'm writing. I almost always begin writing from a central image, usually visual, and I very rarely know where I'm going until I get there. Sometimes not even then, truth be told. A lot of the fun for me as a writer is arriving at the ending and going "aha!" or "oh, cool."
However, I'm not really channeling the story. The thing is, my preparatory thinking seems to go on almost entirely down inside the subconscious, Damon Knight's "Fred." I've come to this realization partly by watching how I'll be writing along and I'll drop in a piece of foreshadowing. I say, "hmm, wonder what that means?" Twenty-five pages later (or two hundred and fifty pages later) it pays off, sometimes in a big way. The heavily armed clowns riding giraffes in Trial of Flowers were like that. If you've ever read my story "The Water Castle", the bit at the beginning with the father's hair was like that -- I had no idea what it meant until much, much later, but I knew it was important.
There's a somewhat obvious question of cause and effect here. Am I foreshadowing in truth, or is the fact that I tossed yeah so many breadcrumbs out merely priming the pump for later? I truly don't know the answer, all I know is it works pretty well for me. This process is rather difficult to describe, and pretty much impossble to explain in a teachable manner, but it works. I will say that very little of my foreshadowing is retroactively planted, especially in short fiction. Novels require a bit more organizational thinking, but fundamentally I'm still following the headlights through the dark and twisted country of story.
As for the Cloakroom Theory of Ideas I mentioned, it works sort of like this: I hear something interesting on the radio, or see something in the world. For example, a few years ago I heard someone on NPR talking about Red Martyrs, Green Martyrs and White Martyrs in classical Ireland. It caught my attention. I did a little quick research, said, "huh", and a few weeks later wrote "Martyr's Carnival." Where the cloakroom comes into it is when I have an image or an idea that feels story-like to me, I park it in my head.
What does "feel story-like" mean to me? Darned if I know. I literally experience it as a slight tingle, like an itch inside my mind. I can have this feeling dozens of times a day sometimes, sometimes no more than once every couple of days. I certainly don't pursue all these itches, most of them slip away. But plenty stick around long enough for me to do a piece of mental visualization where I walk into a long, narrow room much like the cloakroom of an early grades class. There's a board on the wall with pegs where the coats might hang. I hang the tingly, story-like idea there and wait for it to mature. Then when I'm ready to write a short story (usually a decision governed by time availability and process, rather than the urgent intrusion of a specific idea), I let Fred serve something up from the cloakroom.
(Maybe this is more like hanging meat to age than storing outerwear, but I don't think I want a meat locker in my head, thank you very much. Even I have my limits.)
Sometimes Fred throws me a story with a core idea that I don't remember ever hanging up. Either another idea transmogrified, or that one rose voluntary from the deep seas beneath my surface self. Sometimes Fred throws me something that just doesn't work well on the page -- a maypop of a story. Something like 20% of my first drafts fall down the memory hole due to this effect. I save them all, because I never know when I'm going to want an idea back.
So to the question which was asked, to wit, how did I pull five stories out of my head in one weekend? A series of invitations and market opportunities had been piling up in my inbox. I hadn't hung core images for those, but I had hung market guidelines in my cloakroom based on what was asked. So these had time to be wrassled by Fred, and when I was ready to write, there was something to reach for. Could I do it cold? Probably. Could I bang out five different, worthwhile stories cold? I don't know. I'd like to think so, but that's even tougher than writing five stories for which I already had a decent notion of what was wanted.
The two things that have stuck in my head the last few days, landing in the cloakroom of ideas:
-- A robin, puffed up, shivering in the deep snow here waiting for warmth and food. Sharp color contrast, animal misery, the weird and deadly beauty of nature. Something ironic or sad, I don't yet, but the visual image was striking, as was the symbolism.
-- A BBC World Service story on Omaha's NPR station from earlier this week about an orphanage in Nepal which takes AIDS babies. The journalist mentioned a listless, unresponsive girl of five or six who was wearing a blue skirt and a white cardigan, sitting on a chair waiting to die. The orphanage director talked about the children making their own coffins. This nearly made me cry as I drove down Blondo -- all I could imagine was the Child in that situation. She wears clothes like that, she's Asian, she began life in an orphanage. I haven't been able to get that poor girl out of my head since. That story is going to be a stone, murdering bitch to write, but it will come out.
Watch this space for more details.