First, you must have a realistic expectation of the costs involved in attending graduate school: It can be very expensive. Financial assistance exists in several forms. Listed below are brief descriptions of the types of aid available for graduate students beyond Federal loans.
Awarded by federal and local governments, private organizations, and institutions of higher education, fellowships and grants come in different types and amounts. Many provide tuition and a stipend. Most are awarded on the basis of academic merit; therefore, it is important to apply for those that match your interests and strengths. Not everyone will be eligible to compete for major national awards, but there are other, less well-known fellowships and awards that are worth investigating.
Some schools will have an internal fellowship for an outstanding incoming student. Look for these on the program website.
Teaching Assistantships: These are most typically awarded to second semester or second year graduate students, though some may be available during your first semester. Many include a tuition waiver and stipend in exchange for your work--up to twenty hours per week--leading a discussion section, supervising a lab, or grading papers. In some public universities, if an assistantship doesn't cover the entire tuition bill, out-of-state students may only be responsible for in-state tuition.
Research Assistantships: These are also awarded by the institution, and most often to second semester or second year graduate students, though some may be available during your first semester. In return for assisting a professor with research, you will likely receive a partial or full tuition waiver and a stipend.
Employee Work/School Programs: Some employers will help you pay for your graduate education, usually for classes related to the work you are currently doing. Universities often offer their employees the opportunity to take a class or two each semester, at the undergraduate or graduate level. Speak to the human resources office for information and eligibility requirements.
Some schools require a separate application, while others award on the merit of your program application. Also be aware that sometimes the deadlines for applications for these awards are before the grad school application deadline, so know your deadlines!