The essential factor is speed. Given 5 hrs everyone can crack the test, but in 2/3 hrs, how many can solve most of the questions.
One has to time every single practice test and continuously improve the timing.
For the non-quantitative part, plenty of reading is a must. Specially the editorials of major news papers. This is where good vocabulary is used. Also the editor writes about current issues, which helps the reader stay on top of the happenings.
One important aspect: Nobody can crack the complete paper in the given time. So pick-up areas that you are good at and build your speed.