You can get a little gadget that you can always have with you to improve your grip strength. This will give you better racket control and also it will help you reduce the chance of injury.
I keep a “Gripmaster” in my car so I can work on my grip while I’m sitting at stop lights and stuck in traffic. I also have grip gadgets stationed everyplace in the house where I’m just sitting around (like in front of the TV where I’m watching the Tennis Channel).
You could also use a rubber ball or even a dead tennis ball. Just make sure you have some grip gadget placed every place you spend lots of time. — OK for you fanatics. The bathroom is good too.