At all levels, especially beginning levels, one of the most common mistakes is not watching the ball. Not watching the ball causes miss-hits, frustration and loss of confidence.
When I play, I have been trained to watch the ball turn, see the seams rotate, try to spot the lettering on the ball or pretend there is something important on the ball you wish to see in detail. Any of these cues will help you see the ball better.
Sometime watch your friends hit the ball, watch their eyes and head and listen to the hit. You will see that they will have pulled their eyes off the ball before your hear the sound of the ball hitting the racket. Then let them do this for you, they will be able to tell you if you are watching the ball to the racket. Many of my students will swear to me that they are watching the ball, when in fact, they are not tracking it the last four to five feet into the racket.
Try this! As soon as you hit the ball, close your eyes. It is a funny sensation. Most players pull their eyes off the ball too soon because they want to watch their shot go over the net and see if it lands in. Common sense will tell you that your eyes cannot do these two things at the same time, (watching the ball hit the racket and watch the shot stay in the court). Remember that you make the calls on your side of the net and your opponent makes the call on his side of the net. As you become a more accomplished player you will assume that your shots are going in and going where you want them to go. This breeds confidence. Thus, when your focus is on the ball, you create self-confidence, you play better under pressure, you do not take matches so personal and you don't allow your head to be filled with too many details.
More advanced players think about how to attack their opponent, and not as much about themselves. At a certain point in your career you will have had hundreds of thousands of balls under many different conditions and situations. Allow your brain to retrieve these shots by watching the ball and think less. Try it. You'll like it!
Good luck on the court!