This brief 10-minute video explains what a literature review is, and techniques for getting started. (It's just a good resource for anyone doing a literature review, even if they aren't a graduate student.)
This is a more in-depth presentation about Literature Reviews that I did for a Graduate Studies workshop.
Synthesis Matrix for comparing and contrasting ideas/theories
A synthesis matrix helps you record the main points of each source and document how sources relate to each other. After summarizing and evaluating your sources, arrange them in a matrix to help you see how they relate to each other, and apply to each of your themes or variables. By arranging your sources in a matrix by theme or variable, you can see how your sources relate to each other, and can start thinking about how you weave them together to create a narrative.