Your quizzes and midterms will depend specifically on your prof. Quizzes and midterms prepare you for the final. Study hard for them, but do not fret if you have a low score. The key is to score high on the final. Study for the EXAM not the subject. What I mean is study for the questions and style your prof asks, not the way you would answer on say the GREs.
DON'T read and take notes on EVERYTHING.
Priorities:
1. Don't skip classes, and pay attention in class and take good notes in class. Ask good questions. Dumb questions (Yes, there are dumb questions despite what some profs like to premise) are those that should have been answered if a student was paying attention/attended class. Make note of what slides/topics your prof focuses on. These need to be understood!
2. Do necessary readings - this means if you understand it already, don't waste time taking notes and reading about it, unless the text goes in significantly more depth. Figure out a means of reading that fits you - some people like cue cards, some like notes, some like highlighting - some just read. These are all personal, but likewise, some general advice I can provide is not to write everything down! Notes and highlighting are to mark priorities, not rewrite the textbook. Here is a way to think about what good notes are: when your exams come around, you can read what you've highlighted (i.e. REVIEW not RE-READ) and immediately recall what the rest of that paragraph was about. Another way: ***Notetaking is for the purposes of efficient and effective exam review***.
[Exam cramming is a different matter and requires quite a different strategy, but you obviously want to avoid that.]
3. Use your TAs and profs. Don't harass them with long emails (that will just be counterproductive) but send them concise questions. Even better, use office hours. ***This is particularly important in going over tests after you have them graded***.
4. Do this in a group and share notes (discuss them, don't just exchange). This doesn't work for everyone, I never did it myself, but know of many people who did quite successfully. I personally find group study more important for exam review.
5. If you have more time, then you can be more thorough.
6. Much of college is about prioritizing. It is very very difficult to be 100% thorough. Unfortunately, this skill is hard to provide much advice for, it's something you have to adjust based on your own skillsets, goals, and schedule.
7. Have fun and good luck :) This should actually be #1.