I have found that whenever it fails for me, it's likely that I was trying to one-shot the solution and I retry by breaking the problem into smaller chunks or doing a planning work with gemini cli first.

smaller chunks works better, but ime, it takes as long as writing it manually that way, unless the chunk is very simple, e.g. essentially api examples. i tend not to use LLMs for planning because thats the most fun part for me :)