Are you doing 12 of each type of verbal qustion or 12 total verbal questions? Also, looking through a general strategy book (e.g. Princeton/Kaplan/Manhattan) would probably be a good start. In my opinion, you want to learn and and understand the basics of the exam first.

This will also serve as a math refresher. I had not done any geomoetry for a while. I had forgotten some of the rules about triangles, etc. And this showed in my first practice exam. Going through a math section of a strategy book refreshed my memory. Some of the harder concepts I learned/relearned through doing problems, but most of my base came from working through strategy books.

These books also explain good methods/lessons for attacking data sufficiency problems, which for many are an unfamiliar question type.

On the verbal side, many are often unfamiliar with sentence correction and critical reasoning questions. Once again a basic strategy book will give you a foundation to build upon as advance in your studies.

Once you have this foundation, then you are ready to attack questions on a daily basis.

Take an exam after you build this foundation and see what your score is. I can't honestly answer whether or not 600 is possible in that amount of time, since I don't know you. For inspiration, I will tell you that I had a friend who scored in the 400s on his first practice exam and a 730 on the actual exam.

Best of luck and let me know if you have any other questions (or if I can answer this one better).

Thank you for your advice. Of note, the 12 verbal problems I do are the sentence correction, which I find to be a problem. I still work on the other verbal problems as well though.