Do you know there are two types of learning? Explicit is when you are learning something new by taking instruction. For example, taking tennis lessons, initially you will learn different strokes, when to use them, etc.
At the same time you are learning subconsciously. This is Implicit learning. A different part of your brain is involved in implicit learning. Implicit learning will make tennis your second nature. Only way to learn implicitly is by experience, in other words, by playing a lot of tennis. Once you learn something implicitly, you can turn off thinking while doing it. Or once you gain enough experience in tennis, you will just play, your movements will be smooth & you wont think about which stroke to use .
What really interests me is that when you are under pressure or stress, your brain will turnoff subconscious. So everything you learned subconsciously or implicitly wont be available for you now that you need it most. Your brain cannot afford any mistake, so it goes back to your first tennis lessons. Your brain wants to be in 100% control. Explicit system takes over and you will think about every little detail. For example, playing tennis in a tournament or taking an exam. When this happens most people don’t do well or they choke.