1. Explore the web sites of specific government/private agencies based on your topic, e.g. U.S. Department of Labor.
2. Explore research articles on your topic and identify the datasets that are commonly used.
3. When searching the Internet using Google.com, includes site:.gov or site:.edu in your search phrase (to limit your results to governmental or educational web sites, respectively).
Example: "higher education" and (statistics or dataset or "data set") and site:.gov