1) Find key search terms: Use Wikipedia to find keywords, people's names, or place names about your topic. Once you've identified your key search words, try them in various combinations in the library's research databases.
2) Brainstorm other terms that mean the same thing:
EXAMPLE: An article about salary may not use that word, so try terms like wages, pay, income, or earnings. Searching for all of those terms together with OR between them will find at least one of the terms.
3) Use key search terms: In library databases use key search terms that express the most important concepts related to your topic. The more terms you use the fewer results you get.