I have many varied interests, and most require some amount of free work space on my desk. I do not always finish what I've started in one sitting, or one day, or even one week. In the mean time, the space occupied by whatever current project often needs to be cleared for something else. It got to be a drag to have relocate numerous tools, wires, bits of this and that, especially if I had something in a precarious stage of assembly. I can't afford to have a different desk for every project, so I've settled on the next best thing: different self-contained work areas. It's a crazy simple but super effective solution.
Step 1: The limited work area
This is my desktop on a god day. I have a industrial banquet table for my desk, and it holds assorted hardware, such as a 24" monitor, a printer, and some audio equipment. There's a area I clear that's generally sufficient for assembly activity, such as making popup books or hacking on an Arduino.
I've placed two rulers in the picture to give a sense of size.