To add to these good points - for bigger changes, don't just have LLMs restructure your prompt, but break it down into a TODO list, a summary and/or build a scaffolded result then continue from that. LLMs thrive in structure, and the more architectural you can make both your inputs and outputs, the more consistent your results will be.

For example, pass an LLM a JSON structure with keys but no values and it tends to do a much better job populating the values than trying to fully generate complex data from a prompt alone. Then you can take that populated JSON to do something even more complex in a second prompt.