Start with general information from topical encyclopedias, reference sources (like Credo Reference, consumer-focused articles, and even Wikipedia to get a general understanding of your topic.
Jot down terms, studies and important names to use for more detailed searching.
Bibliographies and references at the end of books and articles can lead you toward other resources.
EBSCO Thesauras a.k.a. Subject Terms, Subjects, Headings,