A good design prompt isn't a magic trick. It's a checklist you don't have to remember, run by something that never gets bored.
Make the output reviewable
Lock the parts that never change and leave one slot for the variable. Now every run shares a family resemblance instead of starting from scratch.
Name the failure modes
Treat the first output as a draft, not a verdict. The prompt does the typing; you keep the judgment about what ships.
- Ask for three angles, then cut to the one worth shipping
- Name the audience and the single goal before you generate
- Compare two outputs instead of trusting one
Write down what you never want as explicitly as what you do. The exclusions often do more work than the instructions.