Through the Internet, there is much more information available today than was the case only a few years ago. The information explosion places more responsibility upon the reader to critically evaluate resources.
The following four criteria can help you to evaluate your sources:
Authority--Who is the author? What is his expertise? Who is the publisher?
Accuracy--Is it well-researched? Is there a bibliography or references so you can locate the original source of the information? Do the facts jive with other sources?
Objectivity--Is there bias? Is the information promoting a specific point of view or is it objective?
Currency--Is the information up-to-date? Is it too dated to be useful?
Thinking about any type of publication, including websites, in this way will help ensure that you have located the best information available.
If you would like some real-life examples of how to evaluate materials for your research, the Gingrich Guide, the library's self-paced online tutorial, has a section Evaluating Sources, which specifically focuses on the four criteria above and how to use them.