I had a high school teacher who described what he called a failsafe study method: (1) Take copious notes during lectures, save them in a binder. (2) Every weekday (5 days/week) during the term, read through all class notes from beginning to end. (3) Assuming you've done the above, you won't have to study for a test. But this would only work for memorization-heavy material where all the content is presented during lectures and you're able to write down the contents.

On the other hand, I once had a physics professor in college who spent each lecture rigorously proving the theorems and formulas we'd be using in the homework/tests. Only about 5 minutes (at the beginning) were dedicated to solving problems like what we'd be tested on, and then only in response to specific questions from students. We were pretty much on our own, since most were commuter students (this was Cal Poly Pomona) and couldn't easily come to office hours.