I imagine you know the answer to your question by now, provided you did, in fact, take the exam in early summer. 600 is not bad as a starting point, since the learning curve is steep at first regarding the nuances of the questions. The areas you should study more are those in which you have made the most mistakes. For example, perhaps you fared all right in Reading Comprehension and Sentence Correction, but you could not wrap your head around Critical Reasoning, and your Verbal score took a nosedive as a result. Of course, it would be beneficial to hit CR questions harder in practice. The higher you wanted to push that score, the more time and practice you would have to invest into teasing out your specific weaknesses and addressing them, with or without the help of a study buddy, a tutor, or a teacher.
Best of luck in your studies.