Use an asterisk to substitute for letters at the end of a word (e.g. crit* finds critic, criticism, critique etc.).
Use quotes to search multiple words as a phrase (e.g. "new age" finds these terms in exact order).
Search authors as a subject to eliminate works written by the author instead of about them.
Limit to peer-reviewed (or at least scholarly) articles to find those most desirable for work at the college level. (Peer-review explained: Some journals require articles to be reviewed by other professionals in a particular field before they can be published. These are considered the cream of the crop in scholarly articles.)