Boolean operators (AND, OR, NOT) help make your search more precise.
AND between terms searches for all terms (minorities AND representation AND television)
OR between terms searches for either of the terms, often similar terms (college OR university)
NOT between terms excludes words from your search, this is not used frequently but can be helpful (networking NOT social)
Prepare your search by breaking down your original question or thoughts into the most important search terms. If your research question focuses on the how bullying affects college students mental health, you could have a search that looks like this:
(bullying or cyberbulling) AND (college or university) AND students AND "mental health"