I have recently read an article regarding tackling the GMAT exam. Actually this applies to any standardized testings. It's all about knowing where you stand, understanding your weaknesses and strengeths. So, first you need to discover where you are falling short, for example, some people are really weak on the math section while they excel in the enligh section, vice versa. Once you realized where you are at, then you can choose the right way to prepare for your exam.