Placement of your office furniture, computer armoire or computer desk is also important. Make sure you do not have your back to the door in your office. Don't face a wall while you work, or make the wall "disappear" with a piece of art. The best office space is one that has a regular shape, has at least one window, a solid door that can close and a good place for the desk to live.
Getting rid of clutter is another important Feng Shui tenant. Clutter saps your energy and makes you feel like work is too daunting to ever complete, so creating a system for clearing away debris is a good idea. Mark a day on your calendar for "clutter clear away" and stick with it. You'll be more productive in the long run without intimidating piles everywhere.