If you need a simple, easily-remembered evaluation method, try this strategy, borrowed from journalism, to critique a potential source for your research:
Who wrote it? A individual or multiple persons? A corporate author?
What is it? A book chapter, a book, a print periodical article, a full text article obtained via an online database, a government document, proceedings from a conference, a WWW page?
Where was it published? Name and location of publishing company, name and domain (.edu., .org or .gov) of a WWW site or page.
When was it published or updated?
Why was this resource created? To entertain, inform, persuade? What is its thesis, its point of view, its hypothesis?
How is the item available? In print or electronic form?
For further guidance on source evaluation, see these Grinnell College Libraries tutorials:
Also, here is a list of useful print and WWW-based guides to help you evaluate resources for academic work: