How can I get better at Learning Things?
'Passion' is useless unless it motivates you to acquire knowledge; ideally, it should drive you to do things above and beyond what is required of you.  

Knowledge is cumulative. Technical communication takes place in increasingly complex abstractions. Unless you have the library of primitive abstractions to draw upon, grasping the more complex abstractions is difficult. The only way to gain those simple abstractions is to spend a lot of time thinking about them. 

Drawing things is actually an excellent practice; It has helped me learn for years.