In my case, only recently I learned the value of getting an LLM to write and refine a plan.md architecture doc first, and for it to break that doc down into testable phases, and then to implement phase by phase.

Seems obvious in hindsight. But it took too long to learn that that should be my approach. I had been going phase by phase myself- no overarching plan.md for the LLM.

What Trick of the Trade took you too long to learn?