Classes may be offered by genealogical groups, historical societies, museums, colleges, senior centers, libraries. In one class we made a trip to the state archives. If you do this, try to make it an overnight trip. I sure am glad I took these classes, in the past few years none have been offered. My advice here is to go look for yourself whenever you can do so.
Most libraries have some sort of information.
Even if it is tucked away in a back room on one shelf. This is exactly what I found from personal experience. Later someone told me to call this library about a certain book. I went to a smaller nearby library, found yet more information. You just never know what you many find.