Geography, dates, location, gender & age are just a few of the ways you can narrow your research topic. We recommend starting with one of these resources:
This Keyword tutorial from Auburn University is described as:
This resource is intended for those who need to search a library database in order to find sources for research and writing activities.
Recognize that the careful selection of keywords can help focus your research
Apply strategies to select relevant keywords and synonyms for your own research
The Library of Rush University Medical Center has put together this guide that may help with your search.