It is very important to have the right grip size when selecting a tennis racquet. Having a grip too small or too big will hamper your ability to hold on to the racquet, causing you to have to expend extra grip strength. Using the wrong grip for you is also a common culprit to wrist and elbow injuries. In general, there should be about a pinky’s width of space between the end of your fingertips to the end of the palm. If you have more of a traditional/classic style(meaning you use the continental grip for every shot), then an index finger’s width of space would be fine, BUT no more. Here are a few pictures that depict the proper grip size.

A lot of times, people ask me to re-grip their racquet.  I am always happy to do it for them, since it is easy.  AND here, I’ll show you how it is done.  I am putting on an overgrip here, but it is same concept for a replacement grip as well.