Well first and foremost you have to believe in it more than anyone else. Your main objective cannot be to make money either.
You want to create something that you love and believe in, that you feel passionate about. The commerce side will come after.
I have spent hundreds of thousands of hours pouring myself into my brand, and that is what is required. If you build a product or a brand from a genuine place, your customers or your followers will recognize that. Nothing is more tangible than authenticity.