You may gather background information from a wide variety of resources. Some common resources are subject specific dictionaries, encyclopedias, handbooks, text books, and authoritative web sites. Read a general encyclopedia article on the top two or three topics that you are considering.You may also find relevant background information by talking with your classmates, professors, and reference librarians. Starting with a broad summary gives you an overview of the topic to see how your idea relates to broader, narrower, and related issues. It also give you an idea of some of the terms that are associated with your topic.
A good place to start is by visiting the Database A-Z list (link below), selecting "Reference Databases" from the "All Database Types" dropdown menu.
The resulting database list should include many options to locate background information.