Few-shot prompting
Showing the model two or three worked examples of what you want, instead of describing it.
Also written: few shot, examples in the prompt, one-shot.
Describing a format in words usually gets you something adjacent to it. Showing two or three examples of input and the exact output you want usually gets you the format.
This is the highest-value prompting technique per minute spent, especially for anything with a consistent shape: classification, extraction, rewriting into a house style. Examples are cheaper than adjectives.