Look to your Keyword list for a great starting point.
Step 1: Conduct a Keyword search
Step 2: Find 2-4 results that are relevant to your research
Step 3: Open the results' records and scan the provided Subjects
Step 4: Identify and list which Subjects are relevant to your research
Step 5: Search for those listed terms using the Subject search field
Different databases offer many other Search Fields.
Do not be afraid to try them!