Library databases are organized around concepts. In order to effectively search a database you should first identify key concepts. Once you know what those are you can begin brainstorming keywords that you will use to search. Be sure to think of some keywords that are broader than you topic and some that are more narrow. Here are some tips:
Boolean operators help you when searching. The most popular operators are: AND, OR, NOT.
AND narrows your search, OR expands your search, NOT limits your search
Use the asterisk * to truncate a word and search for all forms.
Ex. Invent* will give you: Invent, Invents, Inventor, Invention
Use the question mark ? as a wildcard symbol.
Ex. Wom?n will search: woman & women
Use quotes to search for a specific phrase rather than just keywords
Ex. "Frog King" will search for the phrase rather than pulling every result that has "frog" and "king" somewhere in the record.