Before retrieving a research item from the library’s shelves or from an electronic database, you can begin to evaluate its usefulness of the source by examining its bibliographic citation.
What is a bibliographic citation? The bibliographic citation is a written description of a book, journal article, or other published work.
Texas A&M library has a good site to assist you in crtically analyzing information sources with a worksheet below to assist you in the process.
Below is a link to a PDF that you can print out to assist you when preparing an annotation. Make sure that you include the main purpose of the text, it's relation to other works in you list, the authors standpoint, ideas, theory or hypothesis, the audience intended and your conclusions.