The way I see it, is that for non-trivial things you have to build your method piece by piece. Then things start to improve. It's a process of... developing a process.

Write a good AGENTS.md (or CLAUDE.md) and you'll see that code is more idiomatic. Ask it to keep a changelog. Have the LLM write a plan before starting code. Ask it to ask you questions. Write abstraction layers it (along with the fellow humans of course) can use without messing with the low-level detail every time.

In a way you have to develop a framework to guide the LLM behavior. It takes time.