One of the interesting things one learns when talking to top players is that they say they are still learning. Some even make it a goal to learn something new each time they play. Do you learn something new each time you play?
You can learn from your opponents; from watching or talking to others; or from your own play. Perhaps your opponent throws a serve at you that gives you trouble - you can learn both how to return that serve and perhaps learn how to do that serve yourself. Or you can learn from some technique he uses, one that you might either incorporate into your own game, or might analyze and decide not to use - and you learn from understanding why that technique either isn’t right or isn’t right for you. Or you can learn from the tactics he uses against you, where you might learn about your own game, and then fix the weak part of your game he is playing into, and perhaps try the same type of tactics against others.
When not playing is a great time to learn - just talk to the knowledgeable players at your club, and you can learn all sorts of things. (One of the best times is to talk to an opponent after you’ve lost a practice match, and get his perspective on what you need to do to improve.) Or watch others play, especially the stronger players who you strive to challenge, and see what it is they do that makes them so strong - and especially look for the root causes of what makes them good. (So it’s not just, “He has a good loop!” so much as, perhaps, “He knows how to set up his loop with his serve and receive, uses placement as much as power, and from lots of practice and good positioning, is consistent.”) Or just think about your own game, especially between matches, and you may learn a lot - from yourself!