For me, one month was sufficient to get 730 (50 on quant and 39 on verbal) and 5.0 on AWA.
I focused on what I was weak in, the sentence correction. The other sections didn't give me issues. I'm strong in quant. Critical reading/reading comprehension were just understanding the reading passages given and extracting the relevent info. I look at studying for the essays. I figured my score there would depend on the topic, whether I knew anything about it. Just brush up on the proper essay formats you were taught in high school (eg intro, argument 1, argument 2, ... conclusion). The only time I was pressured for time was on the essays. I had over 20 minutes left in the quant/verbal sections.
I used the Princeton Review and the official GMAT guide. I found some quant questions on the exam trickier than the ones in the two books. Kaplan's suppose to feature harder questions, but I didn't use it.
Good luck.