Everyone should try to write at least one chapter or even one paragraph of a sacred text. After all, anyone can be divinely inspired.
You can start with a poem or a song, a parable, an origin story, your own cast of deities (or use the names you know, but improve the characters).
What is important to you in a sacred text? What would your ethics look like? What sorts of stories and metaphors would you use? What is important about life, deities, origins, endings, and history?
Your texts will change over time. Look at other texts, read stories, talk to people, try meditation techniques, listen to where you are called.
If you are really stuck, take a piece of a sacred text with which you are familiar and rewrite it to make it your own. Don't worry, it does not offend the deities when you do this, just as long as you do not pass it off as the original.
If you were a divine messenger to humanity, what would you say?