Are you a beginner tennis player that wants to get better? If you are there are a few things you should do. One is make sure you get the right racquet. By the right racquet I mean the racquet that gives you the best chance of simply making contact with the ball. For example switching to a lighter racquet will help increase your ability to make contact.
Now that you have a racquet what is the best way to hold it? Loosely between swings and tighter when serving or returning volley, but you knew that. There are a number of different ways to hold the racquet and serve or return serve. To learn them perhaps it is best that you find an accelerated tennis program rather than a single article covering basics.
Learning the forehand, perhaps the most used shot in tennis is prerequisite for playing the game, and is fairly simple, at least its basic mechanics is. Simply swing the racquet across your body from right to left if you are right handed and left to right if you are a lefty. There is more to it, much more nuance, but every player needs to know the fundamentals. There are a great many more things to learn about tennis. Tons more, more than I have space for here. Seek out a tennis pro in your area, find a tennis program and practice, practice, practice!