|You will find more detailed diagrams in Jeff's book but this is my fast and quick set up for some images. I usually do not use a flashlight as the spot light source, but it made for an easy to photograph this set up. I sometimes use one of my halogen fiber optic lamps as the spot light.
The glass surface I use comes from an 11"x14" picture frame that provides a good place to store the glass when not in use. The glass supports are foam-core board with "duck tape" hinges. The only "gotcha" is the line where the glass back edge passes in front of the background. To avoid having this in your picture (unless you deem it a feature) set the angle on the camera more downward on the tripod. (You are using one aren't you?)
Depending on the lighting and the camera angle you can control the image to either have a reflection in the glass or not. The under glass spot light creates a natural gradation when used, but a nice solid background can also be achieved. If you substitute the solid color paper background for a two or three color mix, then even more variation is possible. See upcoming slides.