A successful search strategy uses both keyword searching and subject searching:
Try a keyword search in the online library catalog. Keywords are natural language terms.
Review the list of results. Look for items whose content matches your research topic.
Once you have identified an item(s), click on the title to view the full information. Review the contenct notes (if available). Note the subject headings which identify relevant subjects that best match your research topic.
Conduct a new search. This time, select a subject search. Use any of the subject headings that you identified in your keyword search.
For tips on searching the online library catalog see this video.