Since you studied for a while already, nothing is new to you. Last last time I took GMAT was over 4 years ago and I still remember many things.
Anyway, what you should do is to sum up what you have already learned. Reading along is never good enough. Read and think will help you a great deal. So start writing some points on paper to sum up some points, rules, reasoning, etc. They will help you especially right before you take the test, as you will feel much assured and well after you go over all the points you have jotted down. Again, physical and mental conditions are so important in test.