Human memories are associative. We always tend to remember an incident by its association to other incident. You can try this exercise, sit idle and close your eyes and let your thoughts flow for few minutes. Now stop the flow of thoughts and traverse back what you were thinking about one by one and think about how you jumped from one thought to the other. The reasons that cause jumping are the association.
Now that we know how it works, we have to practice and implement it for remembering what we read or study. Therefore now we have to learn to deliberately create associations. Here is an article that would help you start: http://www.wikihow.com/Memorize-a-List-Using-Numbers-and-Rhyming-Words
Another efficient way of memorization is using audio-visual techniques. We generally tend to remember movie scenes and songs easily than we can remember our formulae. We can use audio or visual techniques to the same. A Simple visual technique would be using colour pens to write a formula attractively such that we can remember it in the form of a picture or converting a definition into a rhythm to remember quickly.
The above given techniques have proved very efficient to those who use it. A good practice at associating day to day work, study and facts would certainly lead you to perfection in memorizing. If this article helps you or if you have queries regarding the same feel free to comment and connect back.