Try www.scholarships.com. It is a one-stop shop for scholarships across the U.S. You fill out a questionnaire and it does a search for you based upon your responses.
Perhaps the most effective way to find scholarships is to visit the reference librarian at your local library. This person is a valuable asset for this type of search, as there are a myriad of sources to explore - which can be done more effectively and efficiently by eliciting the assistance of this person. Also, this person can find professional associations to which professionals in your career area of interest belong - as many of these associations sponsor or know of such opportunities. The reference librarian should be able to supply you with the name and location and contact person for such professional associations in your local area, so you can contact that person and inquire about such opportunities.
Another good source would be the head of your religious group, if you belong to one, as they sometimes sponsor or know of such opportunities .