With most topics, your problem will not be so much finding sources as figuring out which sources to consult in the limited time you have available. The difference between a useful source and a poor one depends to a great extent on your topic, purpose, and audience. Learning how to tell which sources are best for you allows you to use your time wisely.
Using sources for a purpose
Moving beyond previewing a source
Keeping a working bibliography
Evaluating usefulness and credibility
Reading and interpreting research sources