The following traits often indicate that an article is peer-reviewed:

• A lot of citations: these may appear in-text, and/or as footnotes, endnotes, reference list 
• An Abstract (a brief description of the article)
• The organization of the article into sections such as Methodology, Results, and Conclusion
• Charts, tables, or graphs
• Complex, formal language that is specific to the field
• Notes indicating when the article was submitted and when it was accepted

If you need further help:

• Check out this tutorial on How to Read Scholarly Materials 
• Watch this video on How to Read Scholarly Materials
• Take a look at the guide Research Tips: How to Find Peer Reviewed Articles

You can also Contact the Library with any questions.