Guide
How to write a good AI prompt
Short answer: A good AI prompt says who the AI should be, what to do, the context it needs, the format you want back, and any limits. Specific beats long: a short prompt with the right details usually beats a long, vague one.
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The 5-part prompt formula
Most good prompts, for any AI tool, contain some mix of these five parts. Only the task is essential. Add the others when the result matters.
| Part | What it does | Example |
|---|---|---|
| Role | Tells the AI who to act as | "Act as a senior recruiter." |
| Task | The one thing you want done | "Rewrite my resume bullets." |
| Context | What the AI needs to know | "I'm applying for a marketing analyst role. Here is the job description: …" |
| Format | The shape of the answer | "Give me 5 bullets, each under 20 words." |
| Constraints | Limits and things to avoid | "Do not invent numbers. Keep a confident, human tone." |
Before and after: a text prompt
Weak
Write a cover letter.
No role, no job, no facts. The AI has to guess everything, so the answer is generic.
Strong
Act as a career coach. Write a cover letter of up to 250 words for the Marketing Analyst role at [COMPANY]. Job requirements: [3 REQUIREMENTS]. My achievements: [2 ACHIEVEMENTS]. Confident, human tone. Do not open with "I am writing to apply".
Role, task, context, format and constraints are all present.
You can copy a ready-made version from the cover letter prompt.
Photo editing prompts
When you edit a photo, say what to change and, just as important, what to keep. The most common failure is a face that drifts from the original. Add a line such as "keep my face, features and skin tone exactly the same". Then describe the outfit, background, lighting and style. See the photo editing prompts.
Image prompts
For a new image, lead with the subject, then add style, lighting, composition and aspect ratio. If words must appear in the image, put the exact text in quotes and keep it short. Some tools, such as Midjourney, accept parameters like --ar for the aspect ratio. Weak: "a nice product photo". Strong: "Product photo of a stainless steel water bottle on a pure white background, centred, soft even studio light, subtle shadow, square 1:1, no text." See the image generation prompts.
Video prompts
Write a video prompt like a shot list: the camera framing and movement, what the subject does, the lighting and style, and, if the model generates sound, the dialogue in quotes and any ambient audio. Change one thing at a time between takes. See the video generation prompts.
Common mistakes
- Being vague. "Make it better" gives the AI nothing to work with. Say what better means.
- Asking for too much at once. One task per prompt. Follow up for the rest.
- Leaving out context. Paste the job description, the draft or the photo instead of describing it.
- Not saying what to keep. For edits, name the parts that must not change.
- Accepting the first result. Regenerate, or reply with a specific change.
- Trusting invented facts. Check numbers and claims, and never let the AI make up achievements.
Skip the blank page
PromptUp's prompt builder asks a few questions and writes a detailed prompt for you. Or start from one of 1410 ready-made prompts in the prompt library.
Frequently asked questions
What is an AI prompt?
An AI prompt is the instruction you give an AI tool. It can be a question, a task or a description of an image or video you want the tool to create.
Do longer prompts work better?
Not automatically. Specific prompts work better than vague ones, but padding a prompt with extra instructions can confuse the model. Include what the AI needs and stop there.
Can I use the same prompt in ChatGPT, Gemini and Claude?
For text tasks, usually yes, with small differences in tone. Image and video prompts often need light changes per tool, because each interprets style, camera and text differently.
Is PromptUp free?
Yes. PromptUp is free, needs no sign-up, and runs in your browser. The prompt builder and the prompt library are both free to use.