How to write a better AI prompt for real work

Most bad prompts are not badly worded. They are missing context the model cannot guess: who it is for, what shape the answer should be, and what to do with it next.

The five parts of a prompt that works

The job, said as a verb: summarise, rewrite, draft, compare, extract, plan.
The audience: who reads the output, and what they already know.
The shape: bullet points, a table with named columns, three paragraphs, a list of ten.
One example of good output, if you have one. A single example is worth a paragraph of description.
The constraints: length, tone, words to avoid, what must not change.

A method you can repeat

Write the job in one line. If you cannot, the task is not clear enough for a person either.
Add the audience and the shape. These two remove most of the rework.
Paste one example of output you would be happy with, even a short one.
Say what must not happen: no invented statistics, no new facts, no changing the meaning.
Run it. Fix the prompt, not the answer - edit the instruction, then run it again.
When it works, save it with a name and a note about when to use it. An unsaved good prompt is a prompt you will rewrite next week.

The habit that separates people who get value

Keep a file of prompts that worked, each with one line saying what it is for. Most people lose their best prompts to a chat history they never scroll back through.

Reuse beats invention: the tenth time you run a good prompt you will notice which sentence does the heavy lifting, and you can drop the rest.

One prompt, one job. Prompts that do three things do none of them reliably.
Put the instructions before the material you paste in.
Ask for the answer you can check, not the answer you hope for.

Where this goes wrong

Trusting a name, a number or a quote the model produced without a source you can open.
Asking for a long answer when you needed a short decision.
Rewriting the whole prompt every time instead of fixing one sentence.
Sending private client material to a tool your client has not agreed to. Use what your contract and your client allow, and say what you used it for.

The free tool for this

There is no calculator that answers this one honestly, so here is the free set: eight calculators for rates, quotes, invoices, splits, prices and fees. They run in the page and send nothing anywhere.

If you would rather not build it yourself

Prompt Vault is 79 prompts written for real jobs - invoicing, client updates, listing copy, interviews, study - each with the variables to change and a note on when not to use it. Prompt Vault is $12. See it on the shop, and there is a plain page about it here: what it holds.

Questions people actually ask

Does a longer prompt always work better?

No. Longer helps when it adds context the model cannot infer. Past that it adds noise, and it gets harder to see which line actually controls the output.

What is the fastest improvement?

Say the shape of the answer. 'Three bullets, one line each' fixes more weak prompts than any clever phrasing.