How to win

I spend all of my practice time learning how to play squash. The latest technique I've been working on is the basic grip and the slice stroke. The slice gets lift on the ball and it is the only way to hit a ball that is very near the floor. Another technique I'm still struggling with is the take-back on the backhand. I'm still not comfortable yet with taking the racquet back and up for the backswing. Those are techniques I'm learning to incorporate into play. The more difficult part of practice is learning how to win. Part of that is about discerning what is my mode of performance. In matches or game play, I start slow, peak, and then descend very quickly. What I need is a warmup routine that helps me to start quickly. I've incorporated a 2 minute stationary bike warmup to help get the big muscles in the legs to warm up. I also added a couple of ghosting drills into the match warmup also. The ghosting helps me to remember the rhythm between my footwork and racquet motion. What I still lack is a plan to tackle the short peaking. I'm certain the falloff is caused by a drop in concentration and focus. Fatigue is one cause. A general lack of mental toughness points to another. I could be distracted by a let call I disagree with or let intensity fade when I'm ahead in the score. Ideally I need a way to prevent and regain them once I lose focus and intensity. Aside from willing myself to concentrate, I haven't a clue how to tackle this problem. I am certain this is the key to winning.