GMAT Strategy

I received a PM asking me to comment.

So, to start, get the Official Guide books. Especially for verbal, it's very important to ensure that you are studying from real questions.

Then, as Prasanna said, you're also going to need some GMAT-strategy books that teach you what you need to know for the question types and grammar. Research the different options out there and see what you think would be best for you, and then get something for SC, RC, and CR. SC is pretty different from the other two, but RC and CR are related in some ways (in terms of the techniques you would use), so I'd recommend getting your RC and CR materials from the same company.

If you haven't taken a practice test recently (within the past month), take one that gives you analysis data (so NOT GMATPrep at this point) - you want something that will tell you the time you spend per question, the category into which each question falls (eg: SC, modifiers and pronouns), and (ideally) the general difficulty level of the question. The first two are absolutely necessary; the third one is nice to have.

Use that to figure out your very specific strengths and weaknesses relative to timing, content (grammar rules), and analysis / comprehension (the different RC and CR question types), and technique (how you move through a problem for all three question types).

Then you can actually start attacking your weaknesses! Keep an error log. Every time you get something wrong (or you get right but you know that you got a little lucky and weren't really 100% sure), add a line to your error log. Write down: problem number and source (so you can look it up again), time spent, what you picked, and answers to the applicable questions from this group:
- WHY you got it wrong (not just that you got it wrong)
- why certain wrong answers are tempting / why people would pick them (even if you didn't)
- why those wrong answers are wrong, even though they're tempting
- why the right answer is right
- why someone might not pick the right answer (what would lead the person to think it was wrong when it was actually right?)
- (on ones you got right) why you weren't 100% sure - what was causing your doubt (and this will likely involve at least one wrong answer, in addition to the right answer)
- what you can do to recognize this same grammar issue (SC) or type of reasoning (CR, RC) in the future - for both right AND wrong answers
- how you are going to remember to be able to recognize in future (flash cards? review of these same problems in a few weeks to see whether you remember / recognize? looking for new problems within OG that test the same things so that you can draw connections between the problems? etc.)

Really concentrate on understanding why you are tempted by specific wrong answers and why those answers are wrong anyway. Grammar is all about POE (process of elimination) - find the four wrong answers and cross them off, and you're left with the right answer.