Once the LLM tells me "Okay, it's done, everything works" I always as it to do a thorough review, I tell it to split up the work among sub-agents with each one taking on a specific responsibility (look for code smells, look for bad architecture, review the data access model, DUPLICATE CODE, testability and unit testing, etc.)
After a certain number of revisions and reviews you'll come to accept the shortcomings it comes back. Usually there will be specific design decisions you made that the LLM keeps bringing up, once the review only brings that up and maybe some other minor issues it's time to move on.
I don't overly rely on markdown files and directions. I don't rely on tooling around it either. I just don't trust the LLM when it says "all done", tests pass, and deployment works. I make it to multiple reviews and iterations even when it thinks it's done.
Understand what you're writing. If you never build up the mental model of what the code is doing you'll never be able to discern what is slop and what isn't. There are no shortcuts.
Piling more prompts on might get you to the same end result, but without understanding you'll never know when you're there.