One day I was particularly frustrated because of my overwhelming pile of filing. I had recently changed jobs and in this new position I worked for two busy lawyers and I was used to only working for one, so the filing had doubled. I was mentioning to my co-worker about this problem and she suggested a very simple solution that has helped me manage my filing pile.
She said what she did was take a legal-sized accordion bellows and insert tabs from A to Z. In the short term she would put individual filing in alphabetical order in the appropriate tab. This got the filing off her desk and put in a place she could easily manage. Then when she had a down time she did her filing from the bellows.
The good thing about this system is if your boss needs something quickly, you can go to the bellows and easily retrieve it from the appropriate tab as opposed to going through the pile of filing on your desk and hoping you find it quickly.
This has been a great help in keeping my desk organized and I hope it will be a help to you too.