Shaking out the brain
If you flipped the lid on my brain, turned me upside down, and shook me to see what comes out I strongly suspect it would be: An initial flurry of bats. A couple of conkers and some twigs my niece had me carry. All the quotes from DEBS that live in my head rent free.
After that, not much. If I'm sitting around looking pensive it's not great philosophical thoughts. I'm almost certainly thinking about fictional ladies kissing. Because I've only got one brain cell and it only knows one tune.
David at Forking Mad wrote My Thinking Box which got me thinking about thinking. This is something I know well about myself. How to get myself thinking.
One time I needed to prise a chapter from my mind that very day so I had two showers and went on three walks. (Then wrote a lot of it parked at a supermarket, waiting.) It worked though. Got it done.
The shower (or the toilet, rude, sorry) is a classic example of diffuse mode. How many great ideas have been lost to humanity due to dishwashers taking away the washing up daydreaming space? Staring into the fire. Occupied with something, letting other parts of the mind wander.
My brain works well in motion. So, the car (unhelpful, as I am always driving, sometimes I ask my wife to send me a message then hours later get confused why she's texting me about robots or something), the train, or walking.
Walking is easiest, cheapest, and most environmentally friendly. I like twilight, so somewhere between four (this miserable country in winter) and ten thirty (this beautiful country in summer). Rain is okay, thunderstorms are better. Marching along with my headphones blasting, just sort of gently turning a scene over in my mind. Or potential scene. Or something I'm stuck on. A scene I need. Up to forty minutes to extract one troublesome sentence is fine.
Also good, a very light doze. The problem is it can turn into an actual sleep. This is a well-known trick and popular with creative souls such as Edison and Dali, apparently.
Crucially - crucially! - ideas must be written down or otherwise recorded immediately! I will not remember! Even if it seems such a great idea that of course I will remember it. I will not! And it will torture me.
People will say (often rather sanctimoniously) that you can't wait for inspiration to strike, you have to train it to show up, and so on and so forth. Which is no doubt true. A bit of both, probably.