AI guideBy Erfan Rouhani, developer of PixassoUpdated July 20265 min read
How to write AI art prompts (and negative prompts)
Two people use the same AI generator; one gets murky clip-art, the other gets images people ask about. The difference is rarely the model — it's the prompt. Prompting is a small craft with a handful of learnable rules.
01The four-layer formula
Subject → Setting → Style → Light. Each layer answers one question the model must otherwise guess:
"a knight" → "a weathered knight in dented armor" (subject, specific)
+ "in a birch forest after rain" (setting)
+ "detailed digital painting" (style)
+ "low golden sun through mist" (light)
Order matters: models weight early words most, so lead with what's essential.
02Vocabulary that pulls weight
Some words steer harder than others. Styles: watercolor, oil painting, flat vector, pixel art, cinematic photo, isometric 3D, ink sketch. Light: golden hour, neon glow, soft overcast, dramatic rim light. Quality nudges: highly detailed, sharp focus. Camera terms work on photographic styles: close-up portrait, wide-angle, shallow depth of field. Steal freely from this list — everyone does.
Negative prompt settings excluding unwanted elements from the image
03Negative prompts: the cleanup crew
The negative prompt lists what the image must avoid — and it fixes the classic AI artifacts. A dependable starter set: "text, watermark, blurry, low quality, extra fingers, deformed hands". Then add case-specific exclusions: generating a landscape? Negative "people". A daytime scene that keeps going dark? Negative "night, darkness". One exclusion per problem you actually see — don't stuff it preemptively.
04Debug like a prompt engineer
When a result disappoints, diagnose before rewriting: wrong subject → sharpen layer one; right subject, wrong vibe → swap the style or light words; right everything plus junk → extend the negative prompt. Change one layer per run so you learn what each word does. Ten minutes of this and you'll have a personal prompt template that works across every idea.
Related questions
How long should a prompt be?
One to three sentences covers the four layers without diluting attention. Past that, models start ignoring the middle.
Do capital letters or punctuation matter?
Not meaningfully — commas as separators are plenty. Word choice and order are what move the image.