First of all choose wisely your branch and area of interest and sit for GRE and TOEFL.
Some of the important things to consider are as follows:
An excellent undergraduate academic record especially in your major(70+ to 75+ in some top universities but 60+ would do in most universities. I must inform you that 2/3rd of the test takers score between 400 to 600)
GRE scores(GRE score 130-170 scale in each section verbal and quant and in writing 4 to 6, for some nice top universities).