By learning how to reason well, investigating the evidence, excluding evidence that you can't confirm or even discover to be false, and ascertaining which theory is the best explanation you can find of all the remaining evidence.
For example, what theory best explains the confirmed fact that there is no consistent divine revelation about anything, but instead "so many religions in the world," an endless disagreement over who god is and what he wants? Naturalism predicts this is exactly what we should observe. None of those religious predict this at all, but in fact quite the opposite, as any god would ensure everyone received the same intuitions, revelations, and communications about him. Therefore, Naturalism is more likely true.
Evaluate authorities by investigating many of their claims to fact that contradict other authorities, and then start ignoring as unreliable all the authorities you find most often wrong about those facts.
For example, creationists often misrepresent the facts or even outright lie. If you check their claims, the ones that contradict what actual scientists say, you will find this to be true. The creationists far more often have the facts wrong, the scientists far more often have the facts right. Therefore, you should discount creationists as unreliable and listen to the scientists instead. You don't have to take my word for it. Conduct the investigation I describe. See for yourself.
Question everything. Think for yourself. Learn as much as you can. Do all three things well. And eventually you'll know who's most likely right.
I predict if you do that, you'll find I'm right: naturalism is the only credible worldview.