As cliche as it sounds, I had a dream. It was vivid and it haunted me for a long time (I'm talking months) after I woke up. Then I'd hear a song and it would remind me of that dream, and then the faces crystallized. Voices, names, they all popped out of my subconscious, and the story guided me. After that, it truly depends. It really just has to be an idea, an image, or a similar vision that lingers in my mind until I listen to it. These stories usually nag and nag, so that's why I have so many projects in the works. I let one out and now it's like Pandora's box has been opened.