Researchers can often find useful scholarship by identifying one particularly relevant text and seeing which sources that text cites.
With print texts, this process might involve checking the bibliography. In some databases, you can also trace citations forward in time and find subsequent material that cites a particularly useful resource. Use the databases listed on the "Finding Peer-Reviewed Articles" tab to find a relevant resource and then paste the title of that text into Google Scholar to see more recent texts that cite your original source.
Keep in mind that Google Scholar contains much peer-reviewed literature, but also includes sources that do not qualify as peer-reviewed (for example, master's theses). Be sure to double-check the source to ensure that it's peer-reviewed before using it in your essay.