A literature review discusses published information about a particular topic. As a secondary source, it puts your paper in the wider context of the conversation. A literature review is not simply a list of articles about your topic, rather, it summarizes and synthesizes preexisting research to establish the significance of your paper or to provide background for original research.
The key to an effective literature review is that you analyze studies about your topic in relationship to one another to see what the general lines of thought are regarding your topic, what work has already been done, and what questions still remain to be answered. Part of this process will be to evaluate the methodology used in existing studies, and identify both strengths and weaknesses in the works.
The video below by the University of West Florida provides an excellent explanation of literature reviews.
Literature review formats vary based on discipline, thus you should rely heavily on instructions provided by your professor. In general, the literature review will begin with an introduction. This introduction will lay the background and scope of the literature review, identify search methods and terms, establish any relevant theories, and acknowledge any papers that are considered indispensable to the context for your paper.
This introduction will be followed by a discussion of works which you are including. The length of this section depends on the number of sources used. Note that if you finding hundreds of relevant studies on your research topic, your topic may be too broad. Consider narrowing your research question to focus on a particular aspect of the question. Likewise, if you are not finding any research on your topic, you might need to broaden your research question to include additional source material. All items used in your literature review should directly pertain to your research question.
You will focus on similarities and differences between the works. You will not simply summarize each work in a separate paragraph. That is an annotated bibliography.
For Example:
Considerable research has been conducted on this topic. Authors A, B, and C conducted studies using method one. They arrived at similar conclusions. Authors D, E, and F used a different approach to the problem and discovered something else. The present study builds on this work to answer the question (insert your research question here).