Richard Feynman, the brilliant Nobel physicist and “great explainer”, relied on a simple technique for learning things: Pretend you’re teaching what you want to learn to someone else. It will make you think about your subject enough to explain it. Once you can explain an idea in simple language, you have deeply understood it.
Feynman devised three-steps for “thinking about an idea by explaining it”, outlined in 1 minute in this animated video.
—Pick a topic you want to understand and start studying it.
—Take a piece of paper and write about it as if you’re teaching the idea to someone else. Ideally, write and speak at the same time, just as a teacher does it at the blackboard.
This makes you realize which part you understand and where you still have gaps.
Whenever you get stuck, go back to study and repeat that process until you have explained the whole topic from start to end.
—When you’re done, repeat the process from the beginning but this time simplify your language or use a graphic analogy or examples to make a point. If you’re explanation ends of wordy or confusing, you probably haven’t understood it well enough, so you should start again.
We’ve found that this is an incredibly effective method of learning AND teaching. It’s how we prepare for a talk or workshop, to find the gaps in our understandings and forge a clear message that comes easily, whatever the circumstance.

found at Open Culture
20 year ago, this is how I studied for my State Boards. I would actually go into a classroom and write on the blackboard as if I was teaching a class.
THANK YOU SO MUCH. That is a great and affirming practice.
Thank you so much for affirming this useful practice.