SC: I started with Manhattan SC. Probably the best material on SC around. Like I said earlier, there are some other materials too, but Manhattan is probably the best. The thing I noticed about SC's is that a lot of idioms are tested. And mugging up idioms is not such a great idea. If you have time (I mean couple of months), read some articles on Wall street journal etc. They give a good idea of the idioms used in American English. The most important topics tested on SC are: Subject Verb agreement, Parallelism, Comparison and Idioms. Near the end of my preparation, my accuracy in SC's from OG and OGVR was close to 90% (just so that you have a benchmark). When doing SC questions, I made sure I went through the explanation of each question. Not just the ones I got wrong, but also the ones I got right.
CR: The only thing I studies was how to identify a premise, assumption and conclusion. One piece of advice, don’t get ahead of yourself by assuming too much in any question. I mean the questions are pretty straightforward, and rely only on the information given in the question. Initially I had this problem where whenever I used to read a question, and my mind used to go into overdrive. I used to assume stuff not given in the question. But after a little bit of practice, this was rectified. Another thing, in my experience, if you don’t get a CR question right and don’t agree with the explanation given, don’t worry too much.
RC: I gave GRE sometime ago, and the RC's on GMAT are nothing compared to the ones on GRE. GRE usually has those ‘writers-true feelings’ mumbo-jumbo passages. But the ones on GMAT are pretty simple. My only advise, don’t look to far for the answer. The answer is either directly contained in the passage, or in easily inferred. You don’t have to do any heavy duty thinking to get arrive at the correct answer (specially applicable for the CAT aspirants!). And again, like in the CR's, don’t assume too much. I've heard how people say that breaking a RC into skeletal structure and skim reading is the best way to tackle an RC. But I personally don’t agree. With so much time on your hands, you can actually read the entire passage with ease (and make sense of it too!). At least that’s what I did.
The passages on test day were pretty similar to the ones (topic and structure) in OG and GMATPrep. So do all the passages from there.
AWA: Firstly, read the 800Score AWA guide. That gives a decent idea of how to write essays. Also read the Answers to the real Essay questions, for reasons explained above. I found this site on the internet where you can write your essay online and then submit for others to grade. The best part is that the essay response is timed, so you when exactly to stop. You can also read others' responses.
Here are the links:
I would also advise everyone to write at least 10 essays of each type before giving the exam.
Math: This section was the big surprise. I thought the quant part would be a cakewalk. The questions in OG are way simpler than the ones on the actual GMAT. I just wasn't prepared for the kind of questions GMATPrep and Kaplan
threw at me (Btw, these are the questions you can expect on test day). So I finally sat down and reviewed all math concepts again, just to make sure I remember everything. The hardest questions were probably the DS ones. My accuracy was usually around 85-90% in these. My strategy was simple, first try and solve the question completely with only the info from A. Then with B. Then combine the info from both, and try solving. This was a lengthy procedure, but my accuracy improved with this method. Another thing, don’t think arcane concepts like Harmonic progression, variance, etc. won't be tested on the GMAT. Here is a list of topics you should definitely study, other than your usual quant stuff:
Co-ordinate geometry, especially equations of lines: I got about 3-4 quant questions from this. Learn things like the point-slope equation of the line, 2 point form, the x-y intercepts of lines, slopes etc. Also expect questions like - does this line pass through this quadrant etc.
Statistics: Don’t limit your study to median, mode etc. Read about variance, range, standard deviation and normal distribution. Try and learn all the formula, though these are not really necessary for the GMAT (but they do help). Also understand the practical meaning of these things. Like variance gives you how widely the values are distributed around the mean. These kind of facts really help you on the GMAT.
AP, GP, HP: Yup, you read it right, HP (Harmonic Progression!). Everyone learns the sum to N terms in AP, GP and also how to find the Nth term. Do the same for HP. I actually got a question on test day from HP. That really surprised me. I didn’t remember the formula, but was able to solve it with a little bit of manipulation. But if I had known the formula, I could have saved at least 2 min. And while you are at it, also learn the sum of first N squares and first N cubes.
In GMAT it is not a good idea to try out the process of elimination in Quant. If you've got your basics right, you've got more than enough time to actually solve each and every question. Use your scratch pad generously. Don't be shy to write down the process.