The major point of the book is allowing the unconscious mind, control over the body from the ego mind.
You still want to make changes but you don't focus all of your conscious attention on all the finite details necessary to make the changes during the match , just make a note of it in a broader sense in the mind and allow the unconscious mind to make the necessary adjustments,given that you know the proper technique to begin with.
This comes with practice,as an analogy I teach martial arts, to ingrain a self defense technique into motor memory where it can be used without conscious thought requires around a thousand repetitions. There are over 500 hundred techniques to learn to reach black belt level, but true mastery of the system never comes until you actually quit thinking about the separate techniques and are able to react without thought,we call this flow.
Work on the individual things you want to improve by practicing and drilling,
if you are trying to do this constantly during matches your overall game will suffer because your focus will be too narrow and the conscious mind will have too much control over your play.
Practice,practice,practice, get the technique correct and ingrained until you do not have to think about it during match play.