Cannot reproduce what I have learned or memorised
Your question reminds me of the old joke "How do I get to Carnegie Hall?" To which the response is the same, "Practice, man, practice."

You will be expected to know this stuff when you graduate. When studying any subject, there will be a wide variety of rules and formulae you must learn. Normally, when a teacher is trying to get the students to learn them, the students are given exercises to practice them, or scenarios to apply them.

Learning best works in groups, so if you can find someone with whom to study that should help. You can practice with each other reading your answers to see if you understood correctly. 

If you do not have an exercises or scenarios to use, ask your teacher. But in the end, it is all about practice.