When someone is interested in a topic, there is a heavy intuitive knowledge associated with that interest. A good musician intuitively knows what would be enjoyable to their target audience; a good fashion designer intuitively knows what would be fashionable for the next season; a good personal trainer knows intuitively how to work a particular person with a particular body and a particular mentality to make that person more active and more healthy. In all of these fields and any field you can think of, there is a certain amount of memorization required, a certain set of rules to follow, but is mainly following personal intuition within that field.
Science and math works the same way. Sure, there is a certain amount of memorization involved – terms, history, phrases – but there is a certain amount of intuition involved. There is a logic behind every concept in all of science and math, regardless of terms and phrases. This logic has its beginnings in the appropriate intuition.
Think of your best course in school. You are best at that course because out of all of the courses you have in school, you have the most intuitive sense of that course. You have the best feel for how that topic works than you do about anything else in school.
In order to do better in any course – and have it be easier, as well – you should try to develop this same sense of intuition for the topic. This will take a bit of time and help, but it will make life a lot easier after it's done.