Read something. Close the book. Try to do the thing described. Struggle. Get it right. Repeat until you can't get it wrong. Move on to the next thing. Say you'

Read something. Close the book. Try to do the thing described. Struggle. Get it right. Repeat until you can't get it wrong. Move on to the next thing. Say you're reading a book on programming with some examples to do something such as opening a file and reading it in language X. You read the code example. You close the book, you try to do it from memory. You struggle a bit until you get it right. You start over from a clean slate until you do it casually. Then move on to the next one. A bad way to do it would be to read the example, say "Oh, I get it" and move on to the next example. Test yourself by closing the book. This works for many things. You're watching a video about how to make a knot? Watch the video, then pause it, get a piece of thread/wire/cord, and do it. You most often than not will figure out that you thought you got it but you didn't. A maths/physics/engineering book? Same thing. Read the problem statement. Go over it/try and solve it. Thinking you "got it" is a hypothesis. Aggressively and systematically test hypotheses.