Evaluation is not a black-and-white process; it is rare that a source will be either completely good or completely bad. Examine your information with the following points in mind; remember that certain points may be more or less important, depending on how you plan on using the information. These tips work well for evaluating articles, books, & web resources.
When was the information written? Does it matter to your research if the information is current, or is older information also useful?
Does the information answer your question and meet your requirements? Is it entirely about your topic or are there just a few sentences about your topic? Is the information geared toward your level; is it too advanced or too elementary? If there is an abstract, scan the abstract. Does the description match your topic?
Who is the author/creator? Does he/she have a background that would suggest knowledge of the topic? Is the author associated with a reputable organization? Is contact or biographical information provided?
Where does the information come from? Is it backed up by evidence or just opinion? Is it substantiated in other sources? Are there misspellings and grammatical errors?
Why was the information written? To inform? To persuade? To sell? Are the intentions of the article made clear? Is the information presented objectively? Are there any biases present?
Use this rubric to help evaluate your sources.
Read more about this evaluative process, also known as the CRAAP test.