How will I get maximum scholarships in the US for MS?

Scholarship doesn't depend on just one factor. Your GPA, GRE/TOEFL scores equally matter. Moreover, you need to apply before the scholarship's deadline.

It totally depends on the university and then on your profile that how much scholarship you will get.Generally ,students are encouraged to have paper publications ,research work,internship etc to support their profile so that they have more chances of getting scholarship.