Well, when you have decent shots, it's important that at some point you sit with a pen and think about your game a bit.
-What are your strengths?
-What are your weaknesses?
-And your opponent?
-How can you set up a plan using your strength while covering your weaknesses?
For example, a dude like Federer hadn't a really good BH. However, his slice was knifing, and he had an excellent inside-out FH. So he used his slice CC to force his opponent to lift the ball, and with that weaker reply he played inside-out FH and the point was over. Djokovic has a really good DTL BH, so once he's installed in that CC BH rally, he uses it to open the court, make his opponent play CC to his FH (higher percentage shot) and the point is mostly over.
These are just examples of what the pros do to exploit their strengths on court.