Take the time to find the right search terms. Searching for information is an iterative process, and identifying the most effective keywords often requires trial and error. If your searches aren't yielding the results you expect, try to identify alternate or related terms, or fine-tune your search using some of the strategies below.
Fine-tune your search using
Filters or facets: allow you to narrow your results by source, subject, date range, etc.
Wildcards: in many search engines, the asterisk is a truncation symbol that will match all possible endings for a word stem; i.e. narrat* will match narrator, narration, narrative, narratology, etc.
Booleans: combine search terms using AND (medieval AND "early modern"), OR (gender OR sexuality) and NOT ("dream vision" NOT vr).
When you find a good source, use it to find other good sources. Use the subject terms and keywords associated with an item to find other items on the same topic. Scholarly books and articles will have bibliographies and footnotes that you can mine for additional resources.
If you're not finding what you need, ask a librarian for help. The library staff may be able to suggest additional sources that are directly related to your paper topic.