Using research that has been evaluated by other experts in the field (peer reviewed or refereed) is an efficient way of finding research of value. Some ways to identify if the research is peer-reviewed:

• Use the database: some databases consist entirely (or almost entirely) of peer-reviewed literature (for example: PsycInfo, Sociological Abstracts, Abstracts in Anthropology, ERIC)
• Many databases allow you to LIMIT your search to peer-reviewed or scholarly literature (the EBSCOhost databases like Academic Search Premier for example)
• Check journal's entry in Ulrich's, reference books located at the library Information Desk, with information about almost all periodicals published worldwide, including an icon noting peer reviewed. (NOTE: there is now an online version--it's called UlrichsWeb, see link below!)
• Check the journal's editorial policy statement for an explicit statement (generally small print at the front of the issue, or visit the journal's web page). Look for a list of editors, which can be an implicit indication of peer review.
• Ask a librarian for assistance

Other ways to identify scholarly articles:

• Look for common characteristics of scholarly works, such as
  • easily identifiable author names and affiliations
  • an abstract, introduction, methodology, conclusions
  • citation of others' works
  • a complete list of references
• Determine if article is written by a scholar in the field for other researchers (rather than the general public)

The University of Arizona Library has a web page and tutorial on identifying the differences between popular and scholarly articles at http://www.library.arizona.edu/help/tutorials/scholarly/guide.html