There's a sadness to the human condition that I think music is good for. It gives a counterpoint to the visual beauty, and adds depth to pictures that they wouldn't have if the music wasn't there.
You can do really slow movements with it, like zooming in for a minute and a half. The audience isn't aware that the camera has moved, but there's subconscious tension there.
You make sure that there's a structure that's interesting for them to play on top of, then do temp versions and try it on the film. By the time the players come to the recording session, I've found what works. So I'm not wasting their time.
