The other day I was listening to Skinwalker: Jane Yellowrock by Faith Hunter and my own monster-hunting character formed in my mind. She's tiny, with pixie lineage and she says something like, "My mama always said we were descended from pixies. I've met a lot of supernaturals in my time and none of them were pixies. I think we're just short."
This is how story ideas usually come to me—through character. And often, the character comes with an opening phrase or sentence. Then it's up to me to figure out their story. This time I'm trying to figure out what story world she (I'm thinking Charlotte, which means "petite" in French. I imagine a love interest calling her "mon petite" so it has a double-meaning) belongs in.
At first I thought she'd live in the Knights of Myth and Magic world, but in contemporary times. Then I thought that she should just be in the Minnie Kim world if she's contemporary. Then I questioned all my decisions because life would be so much easier if Minnie Kim existed within the Knights world, which had been my plan but I continue to be conflicted about it all. :P
In speaking with other authors, I think I'm in a small group with my style of story generation. Most people (I think) start with a concept, and then populate their story. I was just trying to think if there was ever a time when I wrote concept-first, and I think Become and Jump Boys: SOS were both concept-first. But once I got to beating the stories, the characters rose up and took over.
Otherwise, they've all been about the character. I wrote "Minnie" (she had a couple different names before) into two or three story concepts before I found where she belonged. Wylie (from my as-yet unpublished Dragon Protocol) showed up with her first scene all fully formed in my mind. Same with Serantha from Blood Crown (no longer available) and Pete from The Swift.
I'll have to keep you posted on what I decide to do with my tiny, feisty pixie-girl, Charlie. It'll be fun to see where she shows up!