As I've mentioned before, I am in the process of editing a western horror anthology. About 1/4 of the stories that come in have no prayer of being taken seriously. The writers who create them have no idea of what the west was like. And they aren't very good at faking it. Some writers don't know much about the Old West, but make up for it with really entertaining plot or at least interesting characters. But what tends to show is when the story is in some unnamed western town where we don't even know what state or territory it's in or the year it is taking place.
My advice if you want to write these type of stories: sit down and create the town you're placing it in. Come up with a town, then come up with the basic folks in that town like the school marm, the town marshal, maybe there's a mayor or preacher. Just start visualizing what this town is like. Then name the place. You'd be amazed to ho w much that helps your story become more believable.
Now, if your story is set on a ranch or some other place that gets tricky. One writer keeps sending me crap set on ranches because I don't think she has a clue what western towns were like. he thing is, she doesn't understand ranch life either. But if you come up with an interesting location, it can really improve your overall story.
I have gone the made up town route, although my western books with Miles O'Malley, and more recently, Fallen Angel, are set in 1880's San Francisco. Growing up in the area, I know a lot about the history of the region and it's just been a natural place or me to base my characters. Ling Fung, from Legends of the Dragon Cowboys, takes up residence in Placerville, which is a California mining town that I selected somewhat because it had a high Chinese population in the 1800's.
My point is, don't just run with a generic town--give us a real place, or a realistic place whether you use a real town or make one up. You'll be amazed how much better your stories will be.