Tennis has so many details, it is too fun to approach your own game with an "analytical" view. In the last ten years, in which I have not played, I followed more tennis on TV and in forums such as these, so I learned a lot about the game. I am using all the tricks to improve my playing.
I noticed I often forget to change grip. I noticed that I should bend my knees more. I noticed I need to turn more my body to the right to hit a forehand. I noticed I should use more "small steps" to correct my positioning prior to the shot. The list goes on... It is real fun to see the improvement after you make the right correction.
But I wanted to tell about a small detail. I had noticed that when I play a match I hit the ball earlier than when I am just hitting (and it makes me go wide frequently). I guess it was just anxiety to hit the ball, and I was having a bit of a hard time to correct this. But the thing is that it was hiding another error, which I found by accident.
I was hitting with someone who was kind of a beginner (I even hit a bit with my "wrong" hand with him, something I like to practice), when it started to rain. We kept on playing until it was possible, and my side of the court got wet first, specially the back court. So I started to play three or four steps inside. Guess what, with that I found out that I was playing too far back -- it is natural, since I came back after a long break, I had lost timing -- so you give yourself more space to make up the time. The price I payed was to hit the ball to far away from my body, when the racquet is well on its way up (in a top spin shot), so more often than I would like my shots would end up wide. Once I realized the positioning was wrong, I solved another problem. This "problem solving" side of tennis is just fantastic.