Hi caviesel,

You never mentioned what books you used to prepare for your first attempt.

Nevertheless, as you have stated that your weaknesses lie in SC and CR, following are the best books people are using and indeed recommending,

1. Manhattan GMAT Sentence Correction - 4th edition (For SC)
2. Powerscore CR Bible (For Critical Reasoning)

Apart from these, get an Official guide 12th edition (must) and practice all its questions if you have not yet practiced them.

Let me know if you need more info!

Thanks papgust.
I have been using the kaplan, the official guide (orange) and the princeton review. But many people told me about the manhattan and I think it´s important to have them. The biggest problem is that until I receive the books the time will have passed by, because they take about a month to get here. What you think about the time of study?
Regards

This will be a very tough ask actually but i would not say that its impossible. If i were you, i would allow at least 2-3 months because you may get burned out before the exam and also you are looking for a 200-point improvement. But if you are really confident that you would come across these hurdles successfully, then start them right away.

As far as resources are concerned, i feel that you already have good resources to score 650+. Whatever books you buy, it depends purely in your ability now to comprehend the concepts properly and apply them in problems. For SC and CR, try the books i suggested. It will be very helpful. I myself got stuck badly in CR, but after learning the concepts and strategies in Powerscore CR bible, my accuracy improved rapidly.

But how confident are you in quants? How much did you score in quants and verbal?

In quant I´m ok. I still have some specific difficults in probability and counting, but anything that I´m not able to manage. My biggest problem are the sc and cr. I´ll try this way, studying like a crazy but i´m more confident and feel is gonna be alright.
Thanks.

You hardly get questions in probability and counting in actual exam, but don't just sit back and not study these topics. One of my friends got 3-4 questions on probability and counting which is of a rarity. So, its worth to at least learn the fundamentals and spend little time with the problems.