This post will deal with the two broad kinds of financial assistance that universities provide MS and PhD students, and how you can go about making your profile such that you get them.
Assistantships include Teaching Assistantships (TAs), Research Assistantships (RAs) and Graduate Assistantships (GAs). In TAship, you assist the professor with teaching responsibilities, such as grading papers and scheduling student appointments. As an RA, you assist the faculty with their research projects. As a GA, you could be asked to organize events, manage university websites etc for the University. The basic difference between these assistantships and scholarships is that here, you have to work for the University to earn the fee waiver and stipend that you’re getting, whereas scholarships don’t require such work on your part.