Yes, lower your expectations! Many times a player will have a very unrealistic approach to a match. They will expect to hit all their shots hard and with control! They will expect to hit perfect shots. In reality, this will set you up for failure. Remember, there is the way you actually play and the way you "wish" to play.
You must deal with reality. Instead of forcing shots that you do not own, settle down. Your average play will probably be good enough to win most matches. Most points are won by your opponent making errors, not you hitting winners. Learn to deal with match pressure. That way, if you start to tighten up in a match, have a plan on how to handle it.
For example, shorten your back swings, lengthen your follow through, hit more balls cross court, stay in the point longer, etc. Going into a match with lower expectations will give you a better chance to win. If you do this and you end up performing better, that will be a pleasant surprise. I believe "choking," (a poor performance), comes from having set your expectations too high.
Good luck on the courts!