While writing, I tend to repeat the same song, endlessly, for thousands of times. This helps me ignore any lyrics, and helps create a consistent mood for each book.
My way of being with people is probably incredibly unhealthy, in that I'll be incredibly social, and I won't write a word for maybe a year, and I'll just be with people, going to parties and soaking up stories, and just sort of recharging all of my ideas.
Some of the best ideas I get seem to happen when I'm doing mindless manual labor or exercise. I'm not sure how that happens, but it leaves me free for remarkable ideas to occur.
The trick to forgetting the big picture is to look at everything close-up.