I don't actually use my real religious faith in my comics... My comics are based on ancient catholic + muslim mythology but in reality I'm of a more pagan faith.
I'd say try not to make it too directly religious - the connection should be more subtle. I do have a story on the way in which the protagonist is a devout christian but is turned into a demon against her will. She struggles with her faith throughout the story but there are other themes at play. I also use other aspects to metaphorically describe religious ideas.
As long as it's subtle people won't be scared away, but I find if the story feels like it's written for christians only then it's far less inclusive and readers can be put off. If you want a broader spectrum of readers then subtlety should be the focus. Religion can be a major factor behind the story without literally being the story.
There are many stories that take a unique angle on the concept of talking to God. I think if you were to include it too literally it might not be as engaging. An example of a good way to do this stuff is Preacher. It inspired a lot of my work, as well. It's got a lot of violence so it might not be for you but it includes a christian protagonist who actually has connections with God and communicates with them, and has power bestowed from heaven. The story is very gritty and dark so there's something unique about it. It explores both healthy and unhealthy ways to be religious, and gets into the mythological stuff too. If you are okay with a bit of blood and over-the-top drama then you might benefit from giving it a read.