Verbal and Writing are the most important categories, yes. But definitely do NOT neglect the math portion...
I would recommend the GRE for Dummies believe it or not...It is dirt cheap first of all. Secondly, it makes studying for it VERY entertaining and VERY helpful because they tell you tips/tricks and show you traps to look out for while making jokes about how the makers of the GRE are horrible people for doing this to you. I kid you not. lol Therefore, the jokes actually help you remember the tips/tricks/traps...lol The only downfall is that it doesn't include very many practice tests so I'd invest in a book of practice exams to supplement it. But seriously check it out on Amazon! you can read the first chapter to see its entertaining and helpful value! 😀 (Im starting to sound like an advocate now... 😛)