Treat prompts as part of a process
Consistent results come from clear tasks, sufficient context and output criteria that can be checked. Treat prompts as part of a process: how inputs are prepared, who verifies the output, and what to fall back on when something fails.
A one-sentence prompt may produce a good result once, but not the same result on the tenth attempt. The difference lies in whether a process exists, not in the wording.
Give the output acceptance criteria
Write the acceptance criteria before the prompt: what counts as correct, what is unacceptable, and who decides. Without criteria, output can only be judged by intuition, and intuition cannot be handed over to the next person.
Set up separate checks for facts, formatting and tone. Keeping these three layers apart makes it clear where a problem lies.
Keep samples and versions
Keep both successful and failed examples, and save a version for every change. These samples are the only regression tests for this work.
This is how prompts grow from one-off inspiration into a production capability the team can maintain.