Many doctoral degrees are funded. This means you'll either receive a stipend and tuition remission in exchange for your labor as a teacher or research assistant, or you may receive a fellowship to fund your studies. Funding should be an important factor in your decision to join a department. If you're not receiving funding, carefully consider whether this particular program is the best fit for you.
If your department doesn't have any funding for you, other departments or agencies on campus might. Check with your campus Career Services Department to find out where graduate funding opportunities are posted, and don't be shy about applying for funding through other departments where your skills can be useful.
If you're pursuing a career in a high-demand field, like teaching or nursing, scholarships might be easier to come by. Look for scholarships within your discipline by browsing career- or discipline-specific organizations. Check out honor societies or professional organizations in your field. Become a member of these organizations; memberships look good on your resumé or CV and may also increase your chances of receiving a scholarship from one of these organizations.
If you were or are a member of a sorority or fraternity, check the North American Interfraternal Foundation's website (nif-inc.net) for scholarship and fellowship opportunities for graduate students.
Try searching Google for scholarships in your discipline.
The U.S. government has a surprising number of funding opportunities available for graduate students. The National Endowment for the Humanities, National Institutes of Health, Environmental Protection Agency, U.S. Department of Agriculture, National Science Foundation, and many other agencies offer grants for graduate students to pursue research or other professional projects. Review the Department of Education's list of funding opportunities for graduate students on their website, students.gov.
The Fullbright Program is perhaps the most famous government-funded graduate scholarship in the United States. If you're considering graduate study and you'd like to teach or research abroad, the Fullbright might be a good option for you. For more information, visit us.fulbrightonline.org.