I would say that for CR, doing many problems will help. With proper practice, you will "see through" the passage and sometimes maybe even guess what the answer will be before seeing the answer choices. Doing LSAT problems will also help you, I discussed this many times already. 1 month before my exam, I did all verbal question from
OG although I do admit that I have seen some of its problems in this forum. Nonetheless, I most likely did not remember most of the questions and answer because the question base is just so broad. In SC, it is not indeed not sufficient to find the grammar error in the sentence: you also have to understand the meaning of the sentence.
OG, I find, is a good source and very representative of the exam although if you depleted most practice material, you could go over 885SC which will be more than enough for the exam. Make sure you keep an
error log and go through your errors a month later so as not to make the same errors again.
The last, and first, time I went through the
OG was 1 year ago. I failed to analyze the questions in a proper way as to "understand" them back then. I got a 650...