You may be surprised what you can find here!
It is difficult to define a topic with much specificity before starting your research. But until you define your topic, you won't know where to begin your search for information and you won't know what to look for. With a well-defined topic, you can focus your search strategies to find lots of relevant information without also finding a lot of useless stuff.
See the library's guide to How to Identify and Develop a Topic which walks you through the steps of selecting a topic for your research.