Do some background reading. No matter what the class, you can check out the following to get a general sense of your topic:
The video below, created by the now-defunct Cooperative Library Instruction Project, explains that you cannot cite Wikipedia as a source for your academic paper. (Just like you would never cite any other encyclopedia!)
However, reading articles on Wikipedia, just like in any other encyclopedia, is a good way to get an overview of your topic. You can find keywords and background information, which you can then use to search more effictively through the library catalogue or journal databases for scholarly sources.
You can also use the Wikipedia article's References list and External Links to help you find more sources.