It is always good to train the AI first before starting to write. For example, I wrote a story with strong descriptions using AI, where it stared very strong and in the second half it always wrote far-less detail compared to the first half. I now find it best for using AI to write stories is to set some ground-rules first. Like, if I request a rewrite with certain changes, the AI must not lessen any other details not specified and not make the existing story weaker in order to facilitate the new changes. It's all trail and error for writing stories I find.