Tennis racquets have come a long way since the sport originated. There are enough rackets available that you should easily be able to find the best tennis racquet for your game. You can buy longer or shorter racquets, racquets with larger heads, wooden racquets, graphite racquets, etc. The choices seem almost endless. There are beginner racquets, and expert racquets.
Weight. The weight of a racquet is very important. Heavier racquets help with control issues, while lighter racquets are more versatile and easier for most people to handle. Lighter racquets also provide better shot control. Mediums weight racquets are right in the middle.
Head Shape. You can buy a standard racquet with an oval head shape. This is the traditional racquet shape. The sweet spot is located on the bottom half of the head. The other option is a tear drop shaped head. This allows for a large sweet spot; almost the entire head of the racquet.
Head Size. A racquet with a larger head size will have a larger sweet spot. It is favored by beginners because the larger head size results in more ball being returned. Smaller head size provides better control, but provides less power. Medium head size means that you will have better control and a larger sweet spot.
It's not a bad idea to have a few different types of racquets if you are an avid player. This will allow you the flexibility to play to your energy level that day.