The continental grip

Okay, you've made it through your first few lessons. Now you are ready to take on volleying and serving. To do both of these, you need to first move your hand into continental grip.
Why should I use continental?
Continental is very useful because it aids in angling the ball directly into the court both at the net and when serving. Because of the way your shoulders are turned when serving and volleying, the continental grip will allow you to line up the ball based on the new angle of your racquet. From the net, your shoulders are only slightly turned, to put your racquet even with the court you need to change the grip on your racquet and therefore the angle.
This is done by moving you hand to bevel 4 if you are right handed, or bevel 1 if you are left handed. Again, your index finger should run up the new bevel and it should fit comfortably in your palm. To check if you are in continental, you can stand still, and try to bounce the ball straight up and down against the ground. If the ball bounces right back up to your racquet, then you need to adjust your grip. This is also useful when serving because of how your shoulders are positioned.
When you serve, your shoulders should be completely even with the lines on the court. In order to make a successful serve, your shoulders must open as you swing. To minimize the amount that they need to turn, you can start in continental grip, taking out some extra rotation and also adding that direct angle towards the ball. Next time you serve, get in position behind the base line. If your shoulders are closed and in normal grip, you should notice that you racquet's angle points directly down the side that you are on. Since you need to serve cross-court, if you start in continental grip, you will notice that just holding the racquet in the air, it is already pointed towards the correct service box.
This grip may feel a little strange at first but I promise you will get used to it. In fact, for some it may even feel better than your normal grip! If that is the case, I encourage you to use it as much as possible. Continental grip, if used correctly, will create natural topspin for your forehand side on the ball, and it will cause that visible arc motion when watching the ball.  Keep in mind though that you may have to readjust your grip for your backhand as the angle is no longer flat, but turned up towards the sky on that side.