Get a Grip on it
Many people, including able-bodied folks, have trouble gripping objects. Screwdrivers, for instance. I can't hold them tight enough to drive a screw into whatever. Jar lids are another. And a big problem for me is my handcycle crank. Twenty-some miles into a ride, my hands are sweaty and slide off the metal grips. Here are a few easy ways to fix the problem.
The best solution for the handcycle crank is at Dick's Sports. It's called an NFL Receiver's glove. It has a plastic or rubbery palm that sticks like glue to anything it touches. No wonder those guys make fantastic catches.
Another easy solution is an old bicycle inner-tube. Just cut out a piece of the tube and either wrap it around the object (like the screwdriver) or you can slip it over the end of a screwdriver and it works like a charm. As long as the rubber is between your hand and the tool, it provides a great grip.
For jar lids, perhaps the best solution is one of those rubber disks you can get at the grocery store.