How to Automatically Clean and Organize Your Desktop, Downloads, and Other Folders

Few people are disorganized because it's their preference. But organization takes time, and however little time it may be, it's generally easier to do nothing than to take a few seconds to file something away in the appropriate folder. Easier, that is, until your desktop ends up looking like this:
 
(Photo by awjmfotos).
Help is on the way with some free software that can automatically clean and organize your desktop. See the link with instructions here. Thanks to Lifehacker for this tip.