How do I use AI to help with writing without it sounding wrong?

The reason AI writing sounds like AI writing is almost always the instruction. Asked for a letter, it produces the average of every letter; asked to tidy up your letter, it produces yours.

Safety

Step by step

1. Give it your material to work from.Write the bad version yourself — bullet points, half sentences, the wrong order — and ask it to turn that into prose. The content, the facts and the voice are then yours.
2. Say who it is for and what it must achieve.'A complaint to a shop about a faulty kettle, firm but not rude, asking for a refund under the Consumer Rights Act, about 150 words.' That produces something usable; 'write a complaint letter' produces filler.
3. Name what you do not want.No bullet points, no headings, no 'I hope this finds you well', no marketing language, no em dashes if you dislike them. Negative instructions are unusually effective here.
4. Give it a sample of your own writing.Paste two paragraphs you wrote and ask it to match the register. It is the most reliable way to stop the default voice appearing.
5. Ask for shorter sentences.The default is long and even. Asking for varied, shorter sentences removes a lot of the machine quality on its own.
6. Use it for the passes it is good at.Shortening to a word count, changing register, checking grammar, finding what is unclear, and suggesting what is missing. All of these are transformation, which is where it is reliable.
7. Ask it to critique rather than rewrite.'What is unclear here, and what would a reader ask?' You keep your own words and get most of the benefit. Often more useful than a rewrite.
8. Iterate on one thing at a time.'Too formal.' 'Still too long.' 'Cut the third paragraph.' Short corrective instructions work better than one enormous initial prompt.
9. Check every fact it adds.It will confidently insert dates, figures, legal references and names that are wrong. Anything it introduced that you did not give it needs verifying.
10. Read it aloud before sending.The fastest test. Anything you would not say out loud comes straight out, and it catches the residual generic phrasing.
11. Keep confidential material out.Names, addresses, account numbers, medical details, anything from work under an agreement. Anonymise before pasting.
12. Be honest about where it is not appropriate.A condolence message, a personal apology, a reference for someone. The value in those is that a person wrote them.

Tips

• Write the bad version first and have it tidied. That one habit fixes the tone problem almost entirely.
• Tell it what to avoid as clearly as what to do. Negative instructions are unusually effective.
• Read it aloud before sending. Anything you would not say is the bit to change.

Common mistakes

• Asking it to write from nothing — With no material of yours to work from it produces the average of everything it has seen, which is exactly the voice people recognise and dislike.
• Sending it without checking the facts — It inserts plausible dates, figures and references that are wrong, and they read as confidently as the correct parts.

If it doesn't work