Take a practice test to evaluate where you're weak and strong at. Since you don't have months to practice, focus primarily on your weakest points.
If you want a good score, you have to actually get serious about it. As in you need to be putting three to four hours a day minimum into studying. Some people do nothing but study for the GRE from the time they get off work to the time they go to bed. It sucks hard, but it is only temporary and nothing in life that is worth having comes without pain and sacrifice.
Take a practice test at the end of every week and do the best you can to simulate the actual test. I like to reserve a study room at my local library when I take practice tests.
I am taking it in a few weeks and I bought multiple books. I've been using GRE For Dummies, NOVA's GRE Math Prep, Manhattan Prep, and The Princeton Review. I got a great deal from Amazon for about $80 for all of them used except the Manhattan Prep because I wanted it new for the multiple practice tests it gives..
Start making flash cards of the most common words. Aim for 100 new words a week. You can get tons of lists of the most common. Here's one of the lists I am using
http://www.examword.com/gre/practice.aspx?co=gl&id=basicgre600words1121222212230261&la=. If you want to go balls to the wall, then aim for 50 a day and at the end of every day, go through the entire cumulative stack of every card you've made up to that point.
For the argument essays, I don't really practice typing them out. I have been learning to identify the logical fallacies and expand on them in my mind. Writing is a strong point for me though, so you may need to practice typing them out. Here is a list of the common logical fallacies
http://www.800score.com/awa folder/awac3b.html
People will go on and on about how the GRE only tests how well you take the GRE, and that is true to an extent, but just like SAT scores for colleges, GRE scores have a very strong correlation with how well a student performs in graduate school. There are outliers and exemptions, but it doesn't change the fact that a student with strong GRE scores is statistically much more likely to succeed in PT than a student with poor GRE scores. It's only one time (hopefully). Take it seriously.