One very easy way to start your research is to look in an encyclopedia that will provide an overview of basic background information on a topic. For example, Wikipedia is an excellent place to get background information. See the WIKIPEDIA guide of more.
eLibrary is an online database paid for by the Library, contains several encyclopedias and almanacs in its Reference section.
Vogue Archive is a resource is perfect for historical research because it has every issue completely available going back to the late 1800s, including ads, articles, etc. All searchable by key word and date range.