Follow all necessary procedures. At the match, sign in, get the balls, and head to the court you were assigned for the warm-up. In the warm-up, feel your opponent out. Try to see what shots he or she is good and bad at, which shot he or she favors the most, etc. Most players tend to go for the forehand and don’t have as good a backhand, so try to hit to the backhand as much as possible.
Test all of the opponent’s strokes (forehand, backhand, volleys). Hit some balls up the middle and see which stroke they choose to hit. This can tell you what their favorite shot is, so keep in mind that it is probably their strength. If you win the toss, choose to serve first, it is easier to hold your serve than it is to break it. Unless you believe theirs is very bad, you can let them serve to gain confidence and get the early lead. On the other hand, if you choose to receive first, this will give you a chance to play some points without the added pressure of trying to hold serve.