I recently attended a brief class about hand held macro photography. The instructor presented a "recipe" for getting good macro shots without having to use a tripod. This is cool because as I quickly discovered, by the time you set up a tripod a lot of things can change or the subject may be gone altogether. The elements of the technique are simple.
1) Use at least a 100mm macro lens
2) Select the flash shutter sync speed for your camera (see my previous blog entry)
3) Use 1/16th power output of your off-camera flash (or diffuse somehow, like with a handkerchief)
4) Set aperture (f-stop) to 16.
5) Set ISO to 100
Attach the flash with a cable and hand hold the flash so that it is even with the front lens element. You may have to play with the flash output a bit, but I got good results with my cheap non-adjustable flash and a diffuser. My shutter sync speed is 1/250 and I experimented down to 1/100. These speeds are fast enough that camera shake is a non-issue. I don't have a macro lens (yet) so I used the macro focus of my Canon 28-135mm lens. You don't auto-focus; set to manual in the macro range and then move the camera back and forth to focus, snapping the shot as soon as you achieve focus. It's a simple technique and it seems to work quite well.