Two techniques reliably sharpen results: specificity and examples.
Be specific about the output. Instead of "make it shorter," say "cut this to under 100 words." Instead of "make it professional," say "rewrite in a formal tone suitable for a client email." Numbers and concrete descriptions beat vague adjectives every time.
Give examples (few-shot prompting). If you want a particular style, show the AI an example. One or two examples of "here's what good looks like" often do more than a paragraph of description.
A Concrete Example
"Rewrite these product names in a fun, punchy style. Example: 'Blue Cotton T-Shirt' becomes 'The Everyday Blue.' Now do the same for: [your list]."
That single example teaches the AI the pattern instantly — far more effective than trying to describe "fun and punchy" in words.
Show, don't just tell — examples are the fastest way to lock in a style.