What makes a good prompt for ChatGPT?
You've tried ChatGPT, but the answers sometimes miss the mark? The problem almost never comes from the tool: it comes from the instruction you give it. That instruction has a name — the prompt — and getting it right changes everything. The good news is it takes only a few minutes to learn.
What is a prompt?
A prompt is simply the message you write to the AI. "Write me a poem", "Summarise this text", "Give me gift ideas"… all of these are prompts. And just like with a colleague you hand a task to: the clearer and more complete the request, the better the result.
ChatGPT's personality
ChatGPT, developed by OpenAI, is a general-purpose, conversational assistant. It's comfortable with a wide range of everyday tasks and works very well through back-and-forth: you ask, it answers, you refine. There's no need to nail the perfect prompt on the first try — the conversation is built for that.
The 5 ingredients of a good prompt
These principles apply to most AIs, but we illustrate them here with ChatGPT.
1. Be specific. "Write a text about dogs" is too vague. "Write a 5-line paragraph explaining to an 8-year-old why dogs wag their tails" gives a clear direction.
2. Provide context. The AI knows nothing about your situation. Spell out for whom, why, in what setting. "I'm a florist preparing a post for my Facebook page" instantly shapes the tone and vocabulary.
3. Assign a role. Telling ChatGPT who it should play often improves the answer: "Act as a bank adviser who explains things simply", "You're a patient history teacher". It then adapts its level and style.
4. State the expected format. Bullet points? A table? An email? 100 words max? Say so. "Answer as a list of 3 points, each in one sentence" avoids indigestible walls of text.
5. Give an example. If you have a style in mind, show it: "Here's an email I like: […]. Write mine in the same spirit." The AI imitates a model very well.
A before / after example
Weak prompt:
Help me write an email to my boss.
Result: a generic email that matches neither your tone nor your actual need.
Effective prompt:
You're my writing assistant. Help me write a short, polite email to my manager asking to work from home on Fridays. Context: I work in a small company, the atmosphere is friendly but we're on formal terms. I want to stay open to discussion, not make demands. Format: 6 lines max, with a subject line.
Result: a message you can use right away, in the right tone, with the subject line as a bonus. The difference isn't down to the tool, but to the instruction.
ChatGPT's strength: the conversation
Don't hesitate to build on its answer rather than rewriting everything:
- "Too formal — make it warmer."
- "Cut it by half."
- "Give me two other versions."
Each piece of feedback refines the result. It's often within two or three exchanges that you get exactly what you wanted.
Tip: ChatGPT also offers custom instructions in its settings. There you can state once and for all who you are and how you like it to respond (for example, "always answer in English, concisely"). Handy for not repeating it every time.
Mistakes to avoid
- Asking for everything at once. For a complex task, break it down: the outline first, then each section.
- Staying vague then being disappointed. If the answer disappoints, it's often because context was missing. Add some.
- Taking it all at face value. ChatGPT can be confidently wrong. For an important figure or fact, verify.
In short
A good prompt for ChatGPT comes down to one idea: talk to it like a competent assistant who doesn't know your context. Be specific, set the scene, assign a role, state the format, show an example — then refine through conversation. That's all that separates a bland answer from a genuinely useful one.
In the next article, we move on to Claude, another major AI assistant with its own preferred way of being addressed.