Ideally, play the course before, so that you know preferable targets. Before leaving the driving range, play the first hole in your mind by aiming at specific targets, using your woods and irons and adjusting the necessary distances to get the ball to the green. Then practice some putting to make sure you have the right feel for the speed of the greens. Decide to deal with non-golf related thoughts after your round. And take some comfort in knowing you are making the most of your time before the tournament.
Amateurs often don t spend enough time warming up before playing.
A recommendation is to have one swing thought that is a positive statement of intent. Usually, if you play the first hole well, negative thoughts will dissipate. If you miss-hit a shot, you have to pay more attention to the next more difficult shot. If you execute a good shot, you will feel confident when faced with another challenging situation. It is preferable not to get too upset or down on yourself after miss-hit shots.