The answer really depends on the subject. Some subjects are highly conceptual and language based. A good way to study for the exams of these types of subjects is to use two techniques called chunking and elaboration. Chunking involves grouping similar bits of information under a category in your mind. When you look at your notes and text, try to order the information in your mind into categories. By doing this what you will find is that when the exam paper is in front you, certain words or phrases will trigger memory recall of certain categories you have formed in your mind. To make sure chunking is effective, you will need to repeat the process a couple of times for the same information. Eventually you will get to a point where you can remember 5-10 bits of information, when you see or think of 1 bit of information that happens to be grouped with them. This is memory theory and it works.
However this is really only rote learning without elaboration. Elaboration is a technique in which after you have chunked the information, you think of hypothetical scenarios or examples in your mind and apply the information you have learned to that scenario. This not only strengthens those connections in your memory, but also dramatically improves your understanding of the meaning behind the content. This allows you to better answer questions that might say, discuss, compare, elaborate and so on. Textbooks or past exam papers also give you hypothetical scenarios that allow you to practice applying the theory and better understanding the meaning behind it.
With the more mathematical and problems based subjects, the best way to learn is to work through practice questions that are as close as possible to what is found on the exam. You must make sure the practice questions you use reflect the style found in the exam. Otherwise you might be able to answer the question, but because of the way it is worded differently you will waste time trying to understand it. Secondly, working through practice questions allows you to understand how to practically apply formula and not just rote learn them.
Before you engage in the practice questions though, make sure you understand the exact meaning of each term and the formula itself. This is critical because it allows you to understand how to apply the formula practically in any situation, not just the ideal one.
For subjects that are a hybrid of the two types, employ both sets of techniques. Get a good nights rest and don't panic!