Listen to
ambient music. Ambient music is supposed to be music that can reward attention (so it's not muzak, or new age fluff), but isn't strict enough to demand it. A lot of it is slow moving, repeated passages, with subtle changes in texture and mood. I like it because I can relax to it, but when I listen, my mind doesn't float away completely. I can pay attention when I feel like but I'm otherwise free to think of other things. I sometimes listen to it while I study.
I find that listening to it before I go to sleep (and as I'm going to sleep) helps me clear my head. My mind doesn't randomly jump from idea to idea because I'm paying attention to the music, but the music isn't completely engaging either. It's not something I'd listen to in the middle of the day, while driving, or something like that. But it's appropriate for other times.
Start with
Brian Eno. Get albums like:
Another Green World
Before and After Science (the second half)
Ambient 1: Music For Airports (
especially this one)
Ambient 2: The Plateau of Mirror
Apollo: Atmospheres and Soundtracks
Thursday Afternoon
The Shutov Assembly
Neroli: Thinking Music Part IV
03007: Bell Studies for the Clock of the Long Now
Also look at Harold Budd:
The Pearl
Lovely Thunder
As Long As I Can Hold My Breath/Avalon Sutra
I also like to listen to (off the top of my head):
Patrick Cassidy & Lisa Gerrard - Immortal Memory
Gaudeamus - Sacred Feast