“The act of writing is the act of discovering what you believe.”
Start with the phrase, “I believe,” and then complete the sentence. “I believe in magic.” “I believe it’s more important to have a clean house than it is to eat vegetables for dinner.” Then use, “I believe,” again, for the start of the second sentence. And the third. And the fourth. Repeat until you have nothing more to say. Don’t think or plan—just write. If you do this exercise well, some of the things you believe should surprise you.