Keep it simple.
You want to include only a few (2-3) words in your searches - the things that that get the heart of what you're looking for
Example:
What is the relationship between amount time spent on social media and likelihood of an eating disorder?
Example:
How was JFK's foreign policy influenced by his religious faith?
Build off these main topics
Consider synonyms/Related Words
Look at Wikipedia/Credo Reference/CQ Researcher
Start broad, then narrow down based on what you're seeing
Google Scholar is a great resource for finding scholarly resources. It is also a great place to check for the full-text of an article before submitting an ILL request.