An NPC named "Rat" — a beast the size of a boot — crouched down, reached for the belt under its jacket and said: "— Neatly done." We fixed that, and a few other things that made worlds sound faceless.
Nature leads — a beast does not speak human words unless the story gives it a reason
Own kit — an NPC knows its abilities and what it carries, so it stops inventing props
World memory — an old enemy walks into the bar and the prose greets him as an acquaintance, not a stranger
Tone and premise — the world's style and the scene's purpose are set by its author, not by the model's averaged taste
Extras 🚶 — NPCs without a story of their own also get a turn, and one who wandered into a strange district knows the way home
And the model finally sees that a character is battered: "10/48 — running out", not a bare number.