I have become interested in the Getting Things Done (GTD) process organized by David Allen. GTD rests on the principle that a person needs to move tasks out of the mind by recording them somewhere. That way, the mind is freed from the job of remembering everything that needs to be done, and can concentrate on actually performing those tasks. The GTD process is summarized in this graphic from a great, free, crossplatform, Java application, ThinkingRock:

Click on graphic for a PDF copy