Historical dictionaries, encyclopedias and biographies are essential reference sources. Consult them to confirm "common knowledge", discover affiliations and related topics, and utilize their bilbiographies to find additional sources, both primary and secondary.
These general studies and overviews are an esssential starting place. TAKE NOTE ESPECIALLY OF THE FOOTNOTES AND REFERENCES - they will lead you to furhter primary and secondary sources.
WHen you find one good book for your topic on the shelves, look around the area and you will likely find others. NOTHING REPLACES BROWSING THE SHELVES AND SERENDIPITY!
Take note of Library of Congress Subject Headings assigned to each record in the catalog. It is a controlled vocabulary, so make a list of specific terms you see there to use in your keyword searches.
Follow subject links to explore the catalog. Many subject heading terms may not be words you would intuitively associate with your topic,
Notice how LCSH are configured, for exampe how and when they include country, state and city names.
Here are a couple examples related to this course:
Noticing the subject headings assigned to books related to your topic will help you brainstorm keywords for furhter searching. Think of every synonym you can for any term related to your topic.
business, enterprise, business enterprise, employer, employee, employment, work, worker, job, career (NB an * is a truncation you can use for keyword searching. e.g. employ* tells the catalog to search for the terms employER, employEE, employMENT etc.)
african american, negro, black, minority
specific occupations: barber, tailor, banking, insurance, record label,