Knowing where to search to find applicable information about your topic is as important as picking out the words you plan to use in your search.
For this activity, go to https://guides.lib.vt.edu/ and look at the broad categories of subjects. Which ones look most relevant to your topic at this level?
From the list, select the broad area that is most applicable to your topic (e.g. Environmental Sciences is located under "Agriculture, biological sciences, and natural resources" to locate subject databases to search.