Keyword searching--Watch this tutorial from the University of Missouri-St. Louis
Boolean operators (AND, OR, AND NOT) These words are used to combine your search terms. Watch the above tutorial.
Truncation--Use the asterisk * to retrieve all variants of a word. For example, environ* will retrieve environment, environmentalist, environmental. But be careful! Con* will retrieve convict, contract, constitution and all other words that start that way. You will get many irrelevant items.
Phrase searching--If your search term is a phrase, e.g., critical thinking, enclose the phrase in quotation marks. "Critical thinking" is a more specific search than typing the words separately.