Everything you know really well, you learned from spaced repetition: doing things many, many times, with time in between each rep or group of reps.
Mastering things in one day doesn’t happen. You might be able to make yourself passively competent (think cramming for an exam in school — you pass the test, and remember none of the information a week later), but getting good in a way that lasts requires your brain seeing and doing it multiple times with gaps of not doing it in between (allowing your mind to clear its mind, if you will).
Tying your shoes. Playing basketball. Speaking a second language. None of these comes in one day. You need to do it, go away, come back tomorrow. And so on. The space allows what you just learned to bake in.
Humans learn best from spaced repetition; this is a fact of science. So I repeat some principles.
I say some things more than once. Use different stories to make the same point. All part of the spaced repetition that will help you not just have heard or read it, but actually know it and use it.
Unlike school, the tests of life don’t offer a make-up course in the summer. What you don’t know will hurt you and cost you. What you have not invested in learning will charge you a late fee plus interest, due immediately.
The good news: it’s an open-book test.