From someone who never studied until college, I can understand where you're coming from.

I always assumed the people who were good at high school were studying, because they were good students inside the classroom and always did their homework. I didn't view the 4.0 kids as thinking that school was easy: they were actually doing homework and paying attention in class. To me that seemed way harder than just studying the night before a test and getting a collection of A's, B's, and C's.

If you we're actually good at high school, unlike me, then you were probably good at going to class and doing your assignments. Even if you only did okay on tests your outstanding homework and other grades would make up for it. I always had to study for tests because I didn't pay attention in class and I needed to make up for losing all the homework points.

To me college seemed much easier than high school because I had way more free time and grades were based almost completely on test scores. I could ignore classes, never do work, not take notes, and just dedicate a night or two to studying really hard before tests.

I went back and clarified my handwritten notes based on what I underlined. Then when I was studying for tests, I would re-write the notes 3-5 times to jam it into my memory.

As someone who was shit at school but great at tests: I highly recommend something like this. My strategy was always to write down by hand anything I wanted to remember a day or two before tests, then make sure I read it immediately before going to bed the day before. I'd read it a few more times the day of the test - repeating it in my head on my way to class. By the time I was in class it was like I had a mental scan of the paper in my head to read from: I could visualize where on the page an answer was and remember what I wrote.

Another good tip is to make anything you want to remember into a joke or rhyme. Doesn't matter how bad the joke is: pick something stupid, the first thing you think of, and tie it to the concept in some way. If you laugh because it doesn't fit the concept at all that's great too, because you'll remember it as the concept attached to your stupid idea. Just tie anything you want to know to something stupid enough that you'll remember it and make sure all your stupid ideas are unique enough that you can tell them apart.