An important step in evaluating a resource is determining if it is considered scholarly. This distinction will need to be made for books, as well as articles.
Finding information & sources generally isn't a problem for students - finding quality, reliable sources tends to be more of a challenge.
It's important for you to take the time to evaluate the sources you discover in the course of your research.
The C.R.A.P. Test is one way of evaluating information, by focusing on the Currency, Relevance, Authority & Purpose or Point-of-View.