Where do you get your ideas?The short answer is: I haven't a clue.
This is the mother and father of all standard questions—probably for all writers. Maybe there is some writer out there who would declare that Why did you make character x in book y run off with the plumber from Vulcan? is their most frequently asked question, but I haven't met them or read their FAQ.
The reason this question makes a lot of writers, including me, wilt, is because there isn't really any answer to it, and trying to say anything genuinely responsive is like trying to break the land speed record on a bicycle. You're not going to do it, and just thinking about it makes you tired. It's the same question really as, 'So, exactly how do you write? Explain.' I was a speaker at a con once whose theme—and therefore what us poor put-upon presenters were supposed to speak about—was more or less this: Describe the writing process from first idea to end of the last page. After I finished laughing/crying I wrote The Whippet Method. But it doesn't answer the question. Where I get my ideas is part of who I am, and while I have some guesses about some of who I am, the mechanism of idea-production is a mystery. I believe human beings are story-tellers by nature, like we stand on our hind legs and are hardwired for learning language, but you're probably born with a really strong story-telling faculty like you might be born with maths ability or sprinting speed. Everyone with two sound legs can run, but not everyone can win a marathon. (I say nothing about everyone's ability to add two and two.)
I tend to declare that my stories 'happen' to me, which is as good a metaphor as any. I will be thinking idly about one thing or another—it might be something as mundane as the shopping list or whether it's supposed to rain tomorrow—and BANG something tears across the horizon of my mind's eye. It's the energy of the thing that tells me it's a story. In the afterword to Rose Daughter I describe it this way: 'If you were picking up stones in the dark, you would know when you picked up a puppy instead. It's warm; it wriggles; it's alive.' I'm an unregenerate daydreamer, but there's rarely any doubt which are the daydreams (Fantasy Writer Wins National Championship Horse Trials!) and which are stories. Stories have lives of their own; the writer is their biographer. I don't make the stuff up: I watch it, listen to it, try to learn more about it, poke into its closets and talk to its friends: and try to write it down as well as I can. Another metaphor I use is that of a notion—or a whim or vagary—'catching fire': I'll be playing with an image, teasing at some little idea, it may be something in a book I've read, a poem, a movie I've seen or conversation I've had or an ordinary sleep-dream--even a bit of daydream wrenching itself out of my egotistical control; something that, again for no reason I can define, gives me a slight tingle of 'something there'. Nothing may come of it; or then again it may suddenly flare up, 'catch fire'. I can't tell you how I do it. I don't actually think I do do it, that's the point. I think it happens. I'm lucky enough that quite frequently it happens in my neighbourhood. But it's that aliveness, that energy, of an idea, that tells me it's a story.
Then comes the really hard part: writing it down. This is the hardest work I know—my usual metaphor is that it's harder than digging out old tree-stumps with a pick-axe, and I speak from experience. The story is always better than your ability to write it. My belief about this is that if you ever get to the point that you think you've done a story justice, you're in the wrong business. Time to trade in your word-processor and become a baker or a mechanic.