In the shower, driving in traffic and falling asleep are all good places to think about ideas. Brainstorming is a waste of time because you can't draw on other people's knowledge that you don't have yourself. The best way for your mind to make connections is for you to have no preconceptions about what it is. It's looking for where to look for it, which shelf, the name of the shelf,. And this is very, very hard to do. There's a discipline of how to do it that comes from Asian martial arts. But the best way to do it is to go to sleep.