One question people like to ask authors is, "where do you get your ideas from?", and the answer, as it should be, is usually some variation of, "where does anybody get any of their thoughts from?" Because really, ideas can come from anywhere. Sometimes they're directly inspired by something we observe, and sometimes, they just form in our brains, either while we're asleep (the "I had this crazy dream..." starting point) or they just appear out of the blue. I personally find that ideas often come to me while I'm already working on another book; something I write, or some plot twist I decide not to use, ends up inspiring a whole new story. The only problem with that is, when the new idea appears, it's suddenly all I can think about (and they always seem to come to me when I hit a creative lull and my brain is looking for something flashy and easy to divert to). When that happens, I usually force myself to jot down everything about the new idea and file it away in my idea folder before returning to my WIP. The new idea can wait its turn. (Sidebar: the word "idea" is starting to lose all meaning as a result of this first paragraph.)
Shiny, new ideas can be dangerous. They're often the death of WIPs. A lot of writers struggle to finish writing anything because they can't stay focussed, and I'd say that 99% of the time, it's best to file new ideas away and stay on task. But the other 1% of the time, when you can't shake the shiny, new idea no matter how hard you try, it might be best to make an exception and let the new idea cut in line. I'm nervous to make the jump, because I don't want to put my WIP in jeopardy of never being finished, but I think the fact that I feel that way is a pretty good indicator that its time will come. With four novels under my belt, I'm at a point where I know I'm capable of reaching the finish line. I think I've earned a little side trip for book number five. Plus, this new idea? It's dark and devastating. Perfect for winter writing :)
Do you find you fall victim to shiny new idea syndrome? Does it keep you from finishing anything or can you set new ideas aside and stay on task?