Learn by Teaching
There are many hacks on how to learn faster. In my experience, the fastest way to learn is to teach someone. Before teaching someone, you have to understand the topic well by preparation. Through preparation and teaching, you will quickly find out how well you understand the subject. Those are the moments where you can improve your understanding. In a nutshell, if you want to know how well you know a subject, pretend that you are teaching it to someone.