The main way would be your local grapevine, ask around, especially your conservatively-minded and financially-astute friends and acquaintances. You have local republican clubs? Well they have treasurers. Know anybody on your local FINCOM (Finance COmmittees)?
Beyond that, the “dry” method, is to check their filings. Start googling. Is a small bank owned by a much larger one? Is it a state-established-bank, or a glowBullista. Look at their federal/state financial reportings.
Good advice - thanks C210N