A prompt is simply what you type into an AI tool, and the difference between a vague answer and a useful one is usually the prompt, not the tool. Here's a four-part method that works in ChatGPT, Gemini, Copilot and Claude alike, with before-and-after examples you can copy.

What is an AI prompt?

A prompt is the instruction or question you give an AI tool. It can be one line ("What's a good name for a cat?") or several paragraphs with background, examples and a pasted document. The AI has no idea who you are, why you're asking or what a good answer looks like to you, unless the prompt tells it. Most disappointing AI answers come from prompts that leave those gaps.

If you're new to AI tools altogether, start with the ChatGPT for beginners playbook, then come back here. And if the words around prompts are unfamiliar, there's a short glossary in what generative AI is, without the jargon.

The four parts of a good prompt

Google's prompting guide for Gemini breaks an effective prompt into four areas, and the same structure works in every AI chat tool:

  1. Persona: who the AI should be, or who you are. "You're an experienced primary school teacher" or "I run a small dog-grooming business."
  2. Task: what you want done. Write, summarise, explain, compare, rewrite, list. Use a clear verb.
  3. Context: the background it can't guess. Who it's for, why you need it, what you've already tried, anything it must include or avoid.
  4. Format: what the answer should look like. Bullet points, a table, three options, under 100 words, a friendly tone.

You don't need all four every time. Google says using a few will help, and that during its testing the most successful prompts averaged around 21 words: a couple of full sentences, not a single keyword and not an essay.

Before and after: AI prompt examples

Each pair below asks for the same thing. The second version adds the missing parts.

A thank-you email

Vague: "Write a thank-you email."

Better: "I'm a parent writing to my son's football coach at the end of the season. Write a short, warm thank-you email, under 120 words, that mentions how much more confident he's become. Keep it friendly, not formal."

Understanding a letter

Vague: "What does this mean?"

Better: "Explain this letter from my energy supplier in plain English, as if to someone who's never dealt with a bill like this. Then list, in bullet points, anything it says I need to do and by when." (Then paste the letter, with your account number and address removed.)

Meal planning

Vague: "Give me some dinner ideas."

Better: "Plan five weeknight dinners for a family of four with one vegetarian. Each should take under 30 minutes and use ingredients from a normal UK supermarket. Put it in a table with a shopping list underneath."

A work task

Vague: "Summarise these notes."

Better: "These are my notes from a team meeting. Summarise them in five bullet points for colleagues who weren't there, then list every action with the person responsible." The meeting notes workflow takes that one much further.

Six habits that improve any prompt

  • Write in full sentences. Talk to it as you'd brief a capable colleague, not as you'd type into a search box.
  • Set limits. A word count, a number of options or a reading level stops rambling answers.
  • Give an example. Paste a message you liked and say "in this style". It's often quicker than describing the style.
  • Split big jobs. Google's guide recommends separate prompts for separate tasks. Plan first, then write, then check.
  • Let it ask you questions. Describe the project, then add: "Before you start, ask me any questions you need answered." It's one of the most useful lines you can learn.
  • Treat the first answer as a draft. Reply with what to change: "shorter", "less formal", "swap the second idea for something cheaper". Refining is normal, not a sign you got it wrong.

What not to put in a prompt

Whatever you type is sent to the company that runs the tool, so leave out passwords, bank or card details, and other people's personal information. Replace names and account numbers with placeholders before pasting a document. If you use AI for work, the checklist for using AI at work safely covers what your employer may expect.

Always check the answer

A well-written prompt gets a better answer, not a guaranteed one. AI tools can state wrong facts with total confidence, so check names, numbers, dates and anything you'll act on. Google's guide says to review outputs for "clarity, relevance, and accuracy" before you use them, and that's good advice for every tool.

Where to go next

The quickest way to get better is to reuse prompts that already work. My free pack of 100 AI prompts for busy professionals gives you a ready-made library, and the five ChatGPT prompts I reuse every week shows how a handful of good ones become a routine. A clear prompt is also what makes an AI agent useful, because an agent can only work towards the goal you describe.

If you'd like to practise with guidance, Your First 30 Days With AI is my eight-module beginner course, and the first two modules are free.

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Questions people actually ask

How do you write a good AI prompt?

Say who the AI should be or who you are, what you want done, the background it can't guess and what the answer should look like. A couple of clear sentences is usually enough. Then refine the first answer by replying with what to change.

What is an example of a good AI prompt?

"Plan five weeknight dinners for a family of four with one vegetarian. Each should take under 30 minutes. Put it in a table with a shopping list underneath." It gives the task, the context and the format, so the answer is usable straight away.

How long should an AI prompt be?

Long enough to include what the AI can't guess. Google found that in its testing the most successful prompts averaged around 21 words, which is roughly two sentences. Longer is fine when you're pasting in a document or examples.

Do the same prompts work in ChatGPT, Gemini and Copilot?

Yes. The four-part approach of persona, task, context and format works in all the main AI chat tools. The answers will differ a little between tools, but a clear prompt improves every one of them.

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