If you want to learn something, one of the best ways to do it is to be conscious of what you are learning. That may sound ridiculously obvious, but life has a way of flooding the mind with too much information and sweeping the newly-learned or almost-learned stuff out to sea.
The best way for me to be conscious of what I’m learning is to literally write what I’m learning down. After every class that I teach (or take) I force myself to sit and write down at least one thing that I learned. Sometimes it’s easy; sometimes not. Usually, the act of writing helps realizations to occur.
I put myself through a course in humor writing by watching funny movies with an agenda: each time I watched, I had to write down at least one thing I learned about why it was funny.
If you’re taking a class, create a ritual for yourself (a mini notebook? a set of 3×5 cards? a dedicated blog?) to write down what you are learning.