Put a old rubber boot mat underneath your grinder to catch any spillage from your grinder.
When grinding a lot of pieces, place a piece of clear float glass over top of your paper pattern. This way, you won't have to grind, dry, test-fit, and repeat. You can just grind and test-fit, quickly going back and forth. Also try to have your pattern where you are test-fitting right beside your grinder, to cut down on time spent just moving back and forth.
Rinse out your grinder sponge often, and replace when it becomes deformed. Also clean out the ground up glass in the bottom of your grinder regularly with a narrow putty knife. Scrape it out into an old plastic container, and then empty the container out when it is full into the garbage.
Move your grinder head up or down when it is getting dull, to a new section, for a better grind. You should be able to get three or four sections out of a typical grinder head. Once your grinder head is worn out, keep it for use as a smooth bit to use on mirror or bevels.