My suggestions:

- like the sister comment says, use the best model available. For me that has been opus but YMMV. Some of my colleagues prefer the OAI models.

- iterate on the plan until it looks solid. This is where you should invest your time.

- Watch the model closely and make sure it writes tests first, checks that they fail, and only then proceeds to implementation

- the model should add pieces one by one, ensuring each step works before proceeding. Commit each step so you can easily retry if you need to. Each addition will involve a new plan that you go back and forth on until you're happy with it. The planning usually gets easier as the project moves along.

- this is sometimes controversial, but use the best language you can target. That can be Rust, Haskell, Erlang depending on the context. Strong types will make a big difference. They catch silly mistakes models are liable to make.

Cursor is great for trying out the different models. If opus is what you like, I have found Claude code to be better value, and personally I prefer the CLI to the vscode UI cursor builds on. It's not a panacea though. The CLI has its own issues like occasionally slowing to a crawl. It still gets the work done.