GMAT Strategy

i received a message regarding this thread.

to the original poster --
there's not much here to go on; all you've given is a bunch of scores (which, by themselves, don't mean a whole lot) and then the names of some materials with which you're preparing.
in other words, the considerations that are actually essential here -- such as what you've actually been doing to prepare -- are notably absent.
HOW did you study?
WHAT did you do?
HOW did you review?
HOW do you think about the problems when you first encounter them in a test situation?
these are the kinds of things that will actually allow us to dispense meaningful advice.

--

in the meantime, here are a few tips for CR in general.

although you may have "gone through" the existing OG problems, there are still plenty of other things that you can do with them -- some of which are arguably more important, in terms of true understanding, than just going through and "solving" the problems.

here are two things you should be able to do with strengthening, weakening, "evaluate the argument", and "explain the situation" problems (which, taken together, represent about 75-80% of all the problems in the critical reasoning section):

1/ MAKE ANALOGIES
you should be able to create a new argument, with different topic material, that proceeds in the same sort of way as the existing argument.

for instance, here is an analogy for #43 in OG12:
Both dieting and exercising will help Ron lose body fat. From experience, Ron knows that dietary changes have a greater impact on his body fat levels than do exercise programs. Therefore, if Ron watches his diet extremely closely, he is doing everything he can do to lose body fat.

--> you'll notice that this argument proceeds in the same way as the existing problem #43 (which i'm not allowed to reproduce here).
however, because it is about topics that are a lot closer to the ground, so to speak -- super mundane stuff like losing body fat -- it's probably a lot easier to understand. in fact, it's probably almost impossible for you to read the argument above without immediately thinking, "why not do both?"

the advantage of making analogies, then, is that it helps you become more intuitive about the process. at the end of the day, CR is basically testing real-world human intuition (as opposed to "rules"), so this is a pretty big deal.

2/ MAKE ALTERNATE CORRECT ANSWERS
the hallmark of problems involving strengthening, weakening, and explaining situations -- just as in the real world -- is that there are lots and lots and lots of ways to strengthen, weaken, or explain something. in other words, there will very rarely be just one way to weaken/strengthen/explain something; instead, in almost all cases, the test writers have simply selected one of many potentially correct answers.

as an example, consider #109 in OG12 critical reasoning. (if you haven't actually solved this problem before, give it a shot before continuing to read.)

the way the correct answer choice works, in that problem, is that it's based on the common-sense principle that people will be less likely to do things if they might get caught. (note that the same principle also makes the problem impossible to solve with "rules"; no one will ever have memorized this principle as a "rule" during any course of study.)
however, that's certainly not the only way to bolster the argument. for instance, the following statement would also strengthen it:
the majority of prank calls made to the fire department are made by teenagers, whose parents monitor their telephone use at home.

if you do these 2 things, you will not only breathe new life into old OG problems, but also reinforce the right mentality for thinking about these problems in the first place (where "the right mentality" means "NOT memorization").