For each source you use you want to make sure it is:
Relevant - Does it answer your research question?
Current - Is the content presented current enough for your project?
Accurate - Is the information provided correct?
Authoritative - Does the author have expertise on the topic about which she is writing?
Objective - Is the information biased? Is the author trying to persuade you to believe a certain way?
Scholarly material is produced by scholars/experts whose credentials can be evaluated. Aimed at other scholars, it disseminates specialized and discipline-specific information, often reporting on original research and experimentation. Scholarly information is a great choice for college students, though it can be challenging to read because of its scholarly language. Scholarly sources are often called academic or peer-reviewed.
Example: Journals like the Journal of the American Medical Association
Popular material is created by journalists, staff writers or freelance writers, and, sometimes, by enthusiasts. This type of information is aimed at the general public. It usually provides a broad overview of topics a general readership will find entertaining. Use popular material sparingly, if at all; for academic work you'll need to be sure to supplement it with articles from scholarly and substantive sources.
Examples: Magazines like People Weekly or Maxim.
See the following criteria to help you identify popular magazines, trade magazines, and scholarly journals.
Nobody has time to wade through millions of web pages. By using a few simple strategies, and Google's advanced search form, you can begin retrieving smaller, more relevant, and more credible web pages.