The way I've found out works best after dog fooding the tool for a while (for resumes, cover letters, etc) is to take an iterative approach to it.
- Start with the minimal amount of info needed.
- Let it generate a "first draft" that acts more as inspiration.
- Fill in a bit more details in various paragraphs. Let it expand on it.
- Delete things that aren't needed.
- Add things you might've initially forgotten about.
- Iterate for a short while and get to hopefully a decent result.
The idea being that the first draft won't ever be perfect. You need a few tries to get to something that's good and truthful for the situation at hand.