Put phrases in quotation marks: "hurricane katrina" "social media" "campaign finance reform"
Use an asterisk * for truncation (to find any ending of a term): communicat* will find communication, communicates, communicating, communicator, etc.
Many different keywords may describe the same or related concepts
(movies, film, cinema, motion pictures)
(refugees, migrants, asylum seekers)
To search for ANY one of a group of terms, use OR and parentheses: (movies OR film OR cinema)
To search for ALL terms, use AND: violence AND movies AND children
COMBINE the above strategies
violence AND (movies OR film OR cinema OR "motion pictures") AND (children OR kids OR adolescents)
SEARCHING IS ITERATIVE
To be effective and thorough, go back and try searching multiple times with many different keywords