From “Mental Models, Investing, and You” P. 15
[A] way to crystalize your learning is to teach it. As they say, ‘Tell me and I forget, teach me and I may remember, involve me and I learn.’ Teaching is one of the most effective (and largely ignored) hack for learning.
So start implementing what you learn and the first step to implementing any kind of knowledge is to teach it to someone else. When you read something interesting, don’t just forward the link to others, make efforts to explain the idea in your words, in your own unique way. When you are teaching to somebody else, it reveals the gaps in your own understanding. You will be surprised with the kind of insights that pop up in your head while you’re explaining new ideas to other people.
so don’t just read, get involved. Don’t just learn, go out and teach.”