Many resources list graduate school programs. Peterson's Guides to Graduate Study and the Barron's Guides are the most comprehensive. National Trade and Professional Associations, a resource found in the Career Services library, lists thousands of associations. If you are an undergraduate, begin researching programs during your junior year. If you have been out of school for two years or more, give yourself at least one year of lead time to prepare your applications adequately.
Most graduate programs require scores from a standardized graduate admissions test.
Make sure you are aware of all application deadlines, such as testing and registration dates, general application requirements, and financial aid deadlines. Procrastination will likely hurt your chances for admission to your first-choice program. Most graduate schools require an essay detailing your career plans and your reasons for pursuing graduate work. Read each school's essay introduction carefully since different schools look for different information. One purpose of the essay is for you to demonstrate how well you follow directions and how clearly you answer the questions.