As I receive mail I allocate it in a variety of ways (more of that in another entry). Something that I've been trying to introduce recently is my "5 minutes" folder. The idea is that if I think something will take a short period of time (5 minutes is a loose measure of time) and it's not urgent (most things aren't), then I put it in my "5 minutes" folder.
Throughout the day as I finish a task, have time between meetings or need a break from something, I turn to the "5 minutes" folder and deal with something from start to finish. It's quite productive and satisfying. By turning to it a few times each day I find that there isn't an accumulation of stuff in it - and if it is getting too full, I know it's time to concentrate on thinning it out.
It works for paper and electronic material, and also for reading stuff. In theory it should work at home as well as work - but somehow I haven't managed to get sufficiently organised at home.