I take a variety of cues from different beliefs.
Most of all, I separate a belief in God from science. If something is supernatural, it inherently can't be tested by scientific methods that we're currently aware of. God would be a being capable of creating the gravitational singularity (an inherently infinite object in terms of mass and energy) that expanded in the Big Bang, meaning God would be a being outside the laws of our Universe. Probably, anyway. Philosophy gets really screwy when you start asking questions like "What is nothing", "What is a pre-Universe", "Is it possible our Universe exists inside of another", etc.
I do believe in a God, but I don't really think modern religion can adequately interpret what a real-life God would be like. I do believe in the religious method of treating others well - as in, I believe in much of what Jesus said, but I think the Bible (and other religious texts) are a mixture of parables, metaphors, and some truth sprinkled with storytelling.
For example; I believe a localized flood probably did occur that inspired the story of Noah, but the Bible made it into a story. We know (factually) that no such worldwide flood could have occurred. There isn't a sufficient amount of water, there is no record of a land bridge from the Middle East to Australia, there's no way herbivores could've survived if all plant life was drowned, there's no archaeological evidence of it occurring, etc.
But we can make an educated guess that the story may have originated from tales passed down from generations that started with a family surviving some flood. It gets exaggerated, details are left out, and it eventually becomes something written in a religious text.