Before you do any searching in the catalog or a database, brainstorm a list of keywords that describe your topic.
woman vs. female
Consider alternate spellings
labor vs. labour
16th century vs. sixteenth century
Consider broader and narrower terms
Great Britain vs. England
Reference materials may help you identify keywords. See the tab above.
Be aware of problems you may encounter:
Homonyms. Remember databases and catalogs match characters, not concepts.
For example, the word "China": is it a country or a set of dishes? The computer can't tell!
Sometimes there is no universally agreed up term or phrase for a concept.
For example, middle ages vs. medieval, Native American vs. Indian, motion picture vs. movie vs. film
Avoid searching for long phrases or sentences. Extract key concepts instead.
The database (or catalog) you are searching may help you choose keywords, because many of them systematically assign subject headings to all works listed within them. Look for the "subject terms" or "descriptors" in the record of a book or an article. These tell you what the preferred term is in a database/catalog and can sometimes help you choose other words to search.
For example, this is a screen shot from Discover Local (the library's catalog). The words in the red circle are the subject terms assigned to this book. If you clicked on the highlighted subject term, Japanese Americans -- Evacuation and relocation, 1942-1945, you would find more works on the same topic.