Nice post and tips! I also use the shower trick to relax and to promote ideas flowing. I never pay attention to the type of ideas, but now that you describe this, I can relate a lot.
"At first, they are the same old ideas I've always had. Then Comes the ideas that are impossible. Then gradually the ideas that could work."
I love the shower one :) I'm glad you can relate hehe
I also like to go to the beach and stare at the ocean or just lay down with my eyes closed. It helps me to think, and it' s very relaxing too. (not good on winter weather...)