True, passion helps. but I have found every time I start a new course and know absolutely nothing about it, my brain is not consuming it at all, so I might have to read a page a couple of times before I get what it is about. And when I kinda get it after maybe 20-30 min it is like I can read on and everything kinda sticks right away. that is, I won't remember specific details, but I can get a simple understanding of what it is about, and that is the key to the rest. It is easier to remember details if you have somewhere to put it in the bigger picture, and from there on one can start to prioritize what details are most important. One can always go back if one needs the lesser details, and then more and more will get stuck. school is usually not about becoming an expert, it is just a general oversight, and you will learn by working after school. having the knowledge about where to look is the key.
But again, what you become passionate about will stick better as you will automatically keep thinking about it when you are not studying. so it is generally a good indication on what you want to do later on in life. But you should be able to get all subjects at a general level.
I also found that 1 page can equal 1 paragraph that you can write. You just write down what you think the page is about in a short summary. don't think about the details. It might be compact so just get what is happening, and take details later.
Example: Learning to drive a car can have pages about rules, traffic signs, how to use the brakes, gas, and even motor details.
A summary here would bee that this is about driving, and we will need to learn about the signs, motor, and how to use the car features. Now you understand what it is about, and that there are different topics that you need to revisit depending on when it becomes necessary.