Finding peer-reviewed articles
Some databases have a checkbox to limit your results to peer-reviewed articles. Others have a tab on the results page for "scholarly articles." If the database doesn't identify the journals as peer-reviewed, look the journal up in Ulrich's International Periodicals Directory; peer-reviewed (refereed) journals have this icon: 
Review articles
A review articles summarizes the research on a given topic. A recent review article can be a great place to start your literature search. The extensive references to the primary research at the end will give you many other articles to explore. The literature review section of a dissertation can serve the same purpose. Many databases will allow you to limit your search to review articles; check the help section of the database for details.
