Most high scorers will tell you to read from books in advance of your classes. They might tell you to read after your classes. They will tell you to listen in class. They will tell you to reflect on what was taught that very day. You've tried it - how come it never works? Why doesn't this work for everyone? It's because these few techniques don't really work like that. Everyone has their own learning style - some people can just read - some people can just get it by listening to their teacher. The fact is: you will never improve unless you learn. Studying isn't about reading, listening or reflecting. It's about learning. If you don't understand what you read, heard, or reflected upon - you didn't learn. Or at least, you couldn't. It's not possible to learn something you don't understand. It's possible to study what you don't understand - but never learn it.
When you learn something, you never forget or at least will always be able to recall what you've learnt. It's what separates achievers from the others. It's the only reason why they appear to perform better - they learn fater and more efficiently. Why do they learn faster? The environment could be more conducive to their preferred learning styles, they could have some serious brain power that exceeds your own, they might have more than one thinking 'language' (I use several ways around a problem - you might try creating your own style or doing such things - there's more than one way to make a box - you don't have to think outside it - you have to think at every angle of the box - not outside yet).
There is always more side to a story - the teacher might choose one way that doesn't suit you - it's important to understand what's the teacher wants to pass on to you - the reason you see a teacher after class is to get her to reveal the angle you're thinking from rather than the angle she showing the rest of the class that you don't quite understand.
The most important part of studying is learning - and if you can't learn - then, follow the next effective habit - don't forget - never put knowledge in short term memory. ;)