Before you can incorporate a strategy into your game play, you first have to establish your capabilities. This includes 1)fitness level, 2)speed of play, 3)racket skillz, 4)mental capacity and 5)court sense.
The easiest of these to develop is fitness level. The cliche "Get fit to play squash, not play squash to get fit" is a paradigm that more people need to develop. Lasting longer on court means being able to train harder before getting tired, and this will translate in to having an easier time on court during a real match. In order to play an attrition based game and run your opponent into the ground, you must be exponentially fitter than your opponent, not just a little bit. How many shots can you play before your mind tells you that you're exhausted?
Speed of play deals with pressure, better players are able to play faster and slower. Moving faster on the court and hitting the ball harder are part of this. Learning to take the ball at different times, early or late, off the ground or off the volley. When you play the ball faster, you take away time from your opponent, when you play it slow, you give yourself time. Learn to control time and space on the court and you will win more matches. How early are you on the ball? How often are you controlling points or are you always scrambling and just hoping to hit the ball?
Racket skillz need perfect practice. 10,000 repetitions makes permanent. if you want to hit a perfect drop shot while on the hard sprint into the forehand corner. Do it perfectly 10,000 times to develop the necessary muscle memory to hit the ball the same way. It takes practice to perfect the cross court volley drop into the nick or even just hitting tighter to the wall. How consistent are your shots?
Mental capacity deals with your ability to focus on the task at hand. Do you know what your trying to do? Winning isn't the answer, it's merely the outcome of accomplishing all the tasks you have set for yourself during the match. The great thing about mental capacity is, once you've conditioned your mind to do things on court, such as learning your footwork, or getting your racket back, it becomes automatic and the only thing you need to do is decide where your gonna hit it. Compare this to riding a bike, once you've taught your feet do the pedalling and your hands to control the handle bars and your body to stay balanced, all you have to do is steer. The bad thing about mental capacity is, once you've made something automatic it really is a bitch to change. What are you thinking about when you are on court?
Court sense is developed from being on court and playing lots of matches, you can train, train, train, but if you never hit the battle field, you will get shot in the heart without ever firing your gun. Learning how the ball comes off the walls, how high it sits off the floor, how it bounces after your opponent hit it in different ways, the movement around another player, the way that you hit the ball, it all changes with every player on every court on any given day. Court sense is being able to see this in your minds eye exactly the same way it plays out in reality. So when you hit the ball, you know where it is gonna go, and when your opponent hits it you know that too. Some people call it anticipation, prepardness or even a inherent sixth sense. How quickly does your mind process everything that's happening on court and then tell you exactly what you need to do to respond?
Once you've established where you are at in your own game you can start to develop your prefered style of play with contingency plans to adapt to multiple player styles.