Writing a literature review is a considerable undertaking. Below are some links to resources that will help you get started on your literature review.
How to (Seriously) Read a Scientific Paper - Comments from master's, doctoral, and post-doctoral students about how they go about reading a scientific paper. Very useful when working your way through articles in a literature review.
Literature Reviews: An Overview for Graduate Students - Even though this is geared towards grad students, it still can apply to work at the undergraduate level.
Literature Reviews (The Writing Center, U. of North Carolina at Chapel Hill)