Like Harmony, I get Shiny New Idea's very often. Whenever I get a new SNI, my mind goes into hyper-drive. I can get a new idea anywhere. My current WIP (the beauty queen zombie book, also known as How Beautiful You Are) I got while staring out the window in the car.
The problem I have with constantly getting new idea's is that once I get one, there's no turning back. I start working on it (because I don't outline) and then I totally forget about any other WIPs. You know when you can hear a character in your head? Sometime they're more quiet and sometimes you have the louder ones? All of my characters are loud and obnoxious. So every month I get a SNI, which means I have this huge folder on my computer that is half finished novels.
I'm now in this awkward stage of writing where I have so many partially done WIPs that I never know which one to write. Even my old and finished WIPs from 4 years ago are still in my head, haunting me. And I don't know why! I have these really angsty rocker voices (4 years ago, I believe I was in 6th grade. And I really liked the whole Hannah Montana idea, so I wrote like 2 books about that sort of thing).
How do you all keep the old voices out of your heads? Or how do you keep so many SNI's from coming up? Let's discuss in the comments!