When you encounter something interesting that you read or listen to, write it down. Keep a journal that you write these down in. In books, use highlighting, underlines, and stars in order to make it easy to locate important concepts.

But to really learn new information and concepts, you first must read or listen to the content, then step away from the material and think about the information you learned. Internally test yourself and rehearse the material. This will show the gaps in your knowledge. One way to do this is to play with the material through writing or teaching it to someone else and having them ask you questions.

When you find your gaps, go back to the primary material. Then wait for a period of time and try to recall it.

It's a cycle of understanding your gaps, finding answers to those gaps, testing yourself and evaluating where your knowledge stops.

You must find the edge of your knowledge that forces you to learn the answers so you can put it together yourself.