Use search tools that limit by "peer review." Standard library research databases that make it easy include:
On the journal's official web site, the publisher should clearly state if the journal is peer reviewed. It may take some looking. You should also be able to find this in the beginning of the journal itself, if you can get the PDF or a print copy.
Search the name of the journal (not the article's title). Try Google or NWACC's official directory to see if it's Refereed:
Check with your instructor or ask a librarian.