The most-asked question of authors is "Where do you get your ideas?"
Give a kid a large empty box and it becomes a cave, a clubhouse, maybe even a spaceship. Kids have no trouble taking something as ordinary as cardboard and creating whole universes.
We all did this when we were young. A towel pinned to the shoulders becomes a cape (Batman phase). An old tennis racket becomes a guitar (Beatles phase). My bike was once a bobsled (I marvel that I survived my Olympic phase). The alcove behind a neighbor's garage was, for eight of us one summer, a detective agency (and no, I never outgrew that one).
What do adults call play? Our games are structured, with fixed rules. Our fantasies become private. Like lions, who as babies wrestled each other to learn how to kill, adults use their old play skills for gain--flirting, scamming, and playing mind control games with bosses and kids.
But in writing--actually, in any creative activity--you get to be a child again, playing "what-if" with whatever happens by. Like the child, the writer's imagination won't be sparked by every little stimulus. Surrounded by toys, a seven-year-old might whine "There's nothing to do!" I feel exactly like this when trying to come up with a story (I try to keep the whining to a minimum). Agatha Christie described the feeling as "broody."
I can never predict what my imagination will grab hold of. I've tried to introduce subjects to it. Other people have tried, too: "Why don't you write a book about such-and-such?" This doesn't work for me. Conscious planning is a left-brain activity, creativity is right-brain. Stories aren't carefully blueprinted and built, like houses. They grow, like living things. And often they grow from tiny seeds, not real ideas at all. No more than glimmers, nudges.
A month before I began BY BLOOD POSSESSED, I had a vague notion that I might write a mystery with a ghost. The whim had a "been done" feeling, though, so I couldn't get started. The seed was a dare from my brother Tom to write a book with two first-person protagonists. I thought it might work, if the two were never in the same scene together and the narrative voices were unique. I played "what-if": What if one voice was contemporary and one historical? What if I tie the modern and historical stories together using the ghost? What if I make the canvas bigger than just a haunted house? Et cetera. The concept went from simple "been done" ghost mystery to a novel about families and war that I had to write.
Idea-growing shouldn't take place at a computer keyboard. The notions need to come together in your head first. Most authors admit that they create stories while doing something boring: driving or doing laundry. Walking seems to help me. Or doing jigsaw puzzles. Christie said she wrote best while washing dishes.
So, where do writers get story ideas? They simply make spaceships out of cardboard boxes. Any child can do that.