Having food handy always seems to help; something to munch while I think and brainstorm. Right now I'm into peanuts because they're tasty, nutritious and don't make a mess. Something to drink too: I like energy drinks (I tried this Neuro Sonic last night and it worked great but Gatorade works too) to get that little 'kick'. I would be munching and drinking and thinking and suddenly DING! It clicks.
Its a mysterious force. Socrates, and many others in his day, thought that rhapsodies went into a trance when they recited plays. 'Divinely inspired' was the term. I read an entire argument in college where Socrates backed one of his friends into admitting he was nothing more than a guy inspired by the gods. I guess that's why I call myself "The Trickster's Scribe". Maybe all that food and drink isn't fuel but instead an offering to my muse.