You will need to do lots of reading n comprehension from as many books u can. This is must. Jus vocabs don't help. For science major maths mus not be dat hard. But make sure u practice like 1 excercise daily. Gre does need lots of time n dedication. Imagine n calculate how much time n dedication u r going to give. Then multiply it by factor of 1.5. Yes gre is dat hard. I have seen so many frens prepare for 1400s n end up wid around 1200. Lastly best of luck n hope my tips helps.