1. Register Early.
2. Prepare for the test. Even if you are an 'A' student, doesn't mean you will do well on the GRE without preparing.
3. Work on what you are not good at, not what you are good at! Students who are good at math will spend their time studying for math! This doesn't help. Focus on what you are NOT good at!
4. You have to do well on both quantitative and verbal. A perfect quantitative score but a weak verbal score or vice versa will hurt your chances of admission.
5. Study in groups – it really helps!