The best thing is to join local groups, give them a small donation and keep up with their website/social media. There is a county or state level conservative group just about everywhere. Where I'm at rurally, we have a regional newspaper, they've had articles on back the blue rallies and BLM rallies in nearby larger towns. It will take some searching and asking questions on local forums, etc. because there isn't usually a one stop shop. Gun forums specific to your state may be helpful or just walk into a local GOP office and ask if there are any local groups you can get involved in.