It could be a little think like not using the right stroke. When I am preparing for a tournament or an important match, I always check to see if my stroke is working. In other words, I focus on each stroke and work hard to be able to switch from one to the other. I lean up my stoke so it will serve me in the heat of a battle. After I determine that I can switch from stroke to stroke, I then work on my speed.
Speed is vital.
This is the proper speed to use in almost every shot in this game. Master this speed and you will win more games. Sometimes during your workout you will find your mind wandering. Here you must snap back to the one shot at a time mode. If I am in a tournament and my mind is wandering, I will become a spectator very soon.