A literature search is a systematic, thorough search of all types of literature (e.g. books, peer reviewed articles, etc.) in prescribed topic. It is a considered and organized search to find key literature on a topic.
When conducting a literature search collecting the information on requesters given topic in an organized manner is essential. Literature searches provide you to read and keep track of many more articles than you would read for an assignment. You may want to try using a bibliographic management tool to help organize the references you have found.