I wish I knew where my ideas came from....
Some of them I can trace. Others, not so much so. Some come from dreams. These tend to be more abstract and in need of polish, especially as they like to contradict themselves. (It made sense while I was asleep! I swear it did!)
Others come from real life, like when I write about trolleys. I take a bunch of things I know about keeping a piece of vintage transit running and wrap a story around it.
Then there's Teleport. That one I know exactly where it came from. One afternoon at work, I was listening to two of my colleagues talk. One asked the other, "What if teleportation was real?" My instant reaction? It wouldn't be good. So, that night I wrote a short story to that end. A few months later, it developed into a novella during NaNoWriMo. Now, some two and a half years on, its finally going through the last stages of editing and should be available soon.
As for the rest? Who knows. They start with a sentence. Then, suddenly, there's a paragraph and I have characters and they're chatting away, wanting things from me. (No one ever warns you going in how needy characters are. Why isn't there a disclaimer on this whole writing business?)
Sometimes, all you have to do is open your ears and listen. There's a story out there. Claim it.