Some essays don't offer an argument—they simply 'cover the topic' in a far too general way.
Essays like this tend to just repeat the information and opinions contained in readings—they are not put to use as evidence for the student's own argument.
Develop a clear argument. This way, the information you borrow from your readings will be put to your own use, rather than being left to speak for itself.
See Five Steps to Better Paragraphs for an example demonstrating how to use your research to present an argument.