City Directories Old-fashioned phone books. Most towns had a directory listing addresses and phone numbers of people who lived in those towns and businesses located in them. They sometimes include other information about the towns, such as population, a map, etc, which can provide some context about your suffragist. (ex)
Census Records are helpful for locating your suffragist's address, family members and their ages and professions. The US takes a census every ten years and it is worth checking multiple censuses. (ex)
Where to find: Ancestry
Vital Records include birth, marriage and death certificates, wills, military enlistment records, etc.
Where to find: Ancestry. County/town historical societies or websites.
School and college records. Yearbooks, college archives, school pictures may be available for your suffragist.
Where to find: local historical societies, college/university archives (hopefully online!)
Newspapers. While these can be tough to track down, there may be articles that mention your suffragist. Your in luck if you can locate an obituary!
Cemetery Records and Gravestones.
Genealogical and town/county histories. It's not so common anymore, but genealogists and historians of the past used to publish books with profiles of prominent locals. Luckily many of these are out of copyright and freely available online. (ex)
Where to find: Google Books or Internet Archive.
Search your suffragist's name, including various forms of her name (with and without middle initial, married/unmarried name). Start with her name in quotes, but try without as well.
Add some detail about her to target results to her, not other people with the same name. This could include her town name, organizations she was involved in, the words suffrage OR voting, or any detail you have about her.
"Mary Wilson" Clarksburg
"Wilson, Mary" clarskburg
Mary E. Wilson Clarksburg
Mary Wilson "West Virginia"
Local Historical Societies and Public Libraries
Many towns and counties have their own historical society that collect an archive historical documents, photos, newspapers, and other material from their area. You may get lucky and locate online collections, but it's more likely you need to contact them to request information or visit them yourself. Check Facebook too!
Do a web search for contact information and search the site below.