Prompt Engineering FoundationsEveryday mistakes and good habits · Lesson 15 of 16
Ten everyday prompting mistakes (and fixes)
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Ten everyday prompting mistakes (and fixes)
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0:00 Everyday prompting mistakes
Most disappointing AI results come from a small number of repeatable mistakes, and once you can name them, you can fix them in seconds. In this lecture you will learn thirteen everyday prompting mistakes, including three newer ones that appeared with thinking modes, file uploads and memory, plus a prompt doctor technique that diagnoses your own prompts. By the end, you will know your personal top two mistakes and how to stop making them.
0:32 Why study mistakes?
Why focus on mistakes? Because a handful of habits cause most disappointing answers, and they are easy to fix once you can name them. It is a bit like learning to drive. You do not become safe by memorising the manual; you become safe by noticing your own recurring errors, like forgetting the mirror, and building a habit that fixes each one. In this lecture we name those errors, so you can spot them in your own prompts in seconds.
1:07 Missing information
The first group is about missing information. Mistake one, the one-line prompt, gives generic results; fix it with context, audience and format. Mistake two, assuming the AI knows your world, produces the wrong product, company or currency; fix it by stating who you are and where you are. And mistake seven, not saying what to do when information is missing, produces invented deadlines, prices or names; fix it with if you don't know, write unknown, or ask me instead of guessing.
1:42 Example 1: 'make my CV better'
A simple example. Someone asks: make my CV better. The AI rewrites everything, adds skills they do not have, and uses phrases they would never say. Which mistakes happened? Vague feedback, no context, and no instruction about missing information. The fix: here is my CV and the job advert; improve the wording of the experience section only; keep every fact accurate; do not add skills I have not listed; and if something would strengthen the application but you do not know it, ask me. Now the edits are targeted, honest and useful.
2:22 Example 2: property listings (illustrative)
Now a business scenario, with illustrative numbers. A property agency in Lahore used AI to write listing descriptions for about one hundred properties a month. Complaints started arriving. Some listings mentioned parking or a garden that did not exist. The mistakes: one-line prompts and no rule for missing information. The team changed their prompt template: include only the features in the property sheet; if a feature is not listed, do not mention it; list any questions for the agent at the end. They also added a quick human check of three facts per listing: size, price and parking. Within a month, complaints about inaccurate listings dropped sharply. The numbers are illustrative, but misleading property descriptions can breach consumer protection rules, so this fix matters beyond customer happiness.
3:17 Conversation mistakes
The second group is about the conversation. Asking for everything at once means half the requests are skipped; number them or break the job into steps. Vague feedback like make it better produces random changes; say what is wrong and why, for example too formal for Instagram, my followers are students. Never starting fresh leaves you in a tangled conversation; start a new chat with an improved prompt. And giving up too early, after one bad attempt, means missing results that usually arrive by the third message.
3:55 Trust and safety mistakes
The third group is about trust and safety. Trusting facts without checking, especially statistics, quotes, sources, and health, legal or financial information. Pasting private information carelessly, such as customer data, passwords or confidential plans; remove or replace personal details and follow your workplace policy. And copy-paste without reading, publishing placeholders like your name in brackets, odd phrasing or claims you cannot support. You are the editor, and you are responsible for the final result.
4:27 Three newer mistakes
Now three newer mistakes. Mistake eleven: using the wrong mode, like waiting two minutes for a thinking mode to rewrite a caption, or asking a quick mode to solve a complex budget. Match the mode to the job. Mistake twelve: trusting an uploaded file blindly. Long or scanned documents, tables and images inside PDFs can be partly missed, so ask for quotes with page numbers and check the key answers. Mistake thirteen: letting memory or old instructions steer you wrong. A formal tone you set months ago may still be shaping today's answers. Review saved instructions and memory every few months.
5:11 Before and after
Here is a before and after. Before: write a product description. After: write a sixty-word product description for our online shop, based in Dubai, prices in dirhams. Product: handmade oud-scented soy candle, two hundred grams, burn time about forty hours from our supplier's spec. Audience: gift buyers aged twenty-five to forty-five. Tone: elegant, not over the top. No claims about health benefits. If you need details I have not given, list them as questions instead of guessing. Then the human step: check the burn time against the label.
5:49 The prompt doctor
Now the prompt doctor. Paste a weak prompt and a short excerpt of the answer you got, and ask the assistant to act as a prompt coach: diagnose which problems it has, such as missing context, vague words, no format, no audience, too many tasks, or no instruction for missing information; rewrite it; and say which single change will make the biggest difference. Compare its diagnosis with your own. Over time you will spot the problems before the coach does.
6:24 Diagnose in 30 seconds
Let us diagnose one prompt together. Write a product description. Which mistakes can you spot? It is a one-line prompt, it assumes the AI knows your shop, and it says nothing about missing information. Now the fix: a sixty-word description for an online shop based in Dubai, with prices in dirhams, the real product details, the audience, the tone, a rule against health claims, and an instruction to list questions rather than guess. Three mistakes fixed in about thirty seconds. That is the speed you are aiming for.
7:02 Recap
To recap. Most poor results come from missing information, messy conversations, unchecked trust, and now the wrong mode, blind trust in uploads, and stale memory. The habit that fixes most of them: before sending, ask, if I gave this to a smart new colleague, would they have what they need? Try this now: for one week, tag each disappointing answer with the mistake number that caused it. Fix your top two first. Next lesson: checking AI work and building your prompt toolkit.
Mistake 1: the one-line prompt
Symptom: generic, bland results. Fix: add context, audience and format. Even two extra sentences transform most answers.
Mistake 2: assuming the AI knows your world
Symptom: the AI refers to the wrong product, invents company details or uses the wrong currency. Fix: state the essentials: who you are, where you are, who the audience is. "We are a UK-based charity; use British English and pounds."
Mistake 3: trusting facts without checking
Symptom: a statistic, quote, legal rule or source turns out to be wrong or invented. Fix: treat factual claims as leads to verify. Ask "Which parts of this are you less certain about?" and check key facts in reliable sources. Be especially careful with health, legal, financial and news topics.
Mistake 4: asking for everything at once
Symptom: half the requests are ignored or done badly. Fix: one task per message, or clearly numbered requests. Break big jobs into steps: outline, then draft, then edit.
Mistake 5: vague feedback
Symptom: "Make it better" produces random changes. Fix: say what is wrong and why: "Too formal for Instagram; my followers are students."
Mistake 6: never starting fresh
Symptom: a long, confused conversation where the AI mixes old and new instructions. Fix: start a new chat with a clear, improved prompt that includes what you have learned.
Mistake 7: not saying what to do when information is missing
Symptom: invented deadlines, prices or names that fill gaps. Fix: "If you don't know, write 'unknown'" or "Ask me instead of guessing."
Mistake 8: pasting private information carelessly
Symptom: customer data, passwords, confidential plans or someone else's personal details go into a tool without thought. Fix: remove or replace personal details ("Customer A"), never paste passwords, follow your workplace's AI policy, and check the tool's data settings.
Mistake 9: copy-paste without reading
Symptom: publishing text with errors, odd phrasing, placeholders like "[Your Name]" or claims you cannot support. Fix: read everything before you send or publish. You are the editor and you are responsible for the final result.
Mistake 10: giving up too early
Symptom: "AI isn't useful for my job" after one disappointing try. Fix: try the T-CAFE structure, an example, and two rounds of feedback before judging. Many tasks that fail on the first attempt succeed on the third.
A before-and-after example
Before:
write a product descriptionAfter (fixing mistakes 1, 2, 7 and 9):
Write a 60-word product description for our online shop (we're based in
Dubai; prices in AED). Product: handmade oud-scented soy candle, 200g,
burn time about 40 hours (from our supplier's spec). Audience: gift
buyers aged 25-45. Tone: elegant, not over the top. Don't add any claims
about health benefits. If you need details I haven't given, list them
as questions at the end instead of guessing.Then the human step: read it, check the burn time matches the label, and remove anything you cannot stand behind.
Spotting a weak answer
Signs you should push back or verify:
- It is very general and could apply to anyone.
- It includes specific-looking numbers you did not provide.
- It cites sources you cannot find.
- It avoids your actual question.
- It sounds confident about something that changes often (prices, laws, schedules).
The habit that fixes most problems
Before sending any prompt, ask: "If I gave this to a smart new colleague, would they have what they need?" If not, add what is missing. This single habit fixes the majority of everyday prompting problems.
Make it stick
Pick the two mistakes you recognise most in yourself and write their fixes on a sticky note or at the top of your prompt toolkit. For the next week, check each prompt against those two fixes before sending. Small, repeated habits improve your results far more than reading long lists of tips once.
Three newer mistakes to add to the list
As assistants gained new features, new mistakes appeared.
Mistake 11: using the wrong mode. Asking a quick-answer mode to solve a complex multi-step problem, or waiting two minutes for a thinking mode to rewrite a one-line caption. Fix: match the mode to the job. Quick mode for drafting and rewriting; thinking mode for multi-step reasoning, calculations and plans; web search or deep research for current facts.
Mistake 12: trusting an uploaded file blindly. You upload a 60-page PDF and assume the assistant read every page carefully. Long or scanned documents, tables and images inside PDFs can be partly missed. Fix: ask for page references ("quote the passage and give the page number") and check the most important answers against the document.
Mistake 13: letting memory or old instructions steer you wrong. Custom instructions, projects or memory from months ago ("always write in a formal tone") silently shape today's answers. Fix: review your saved instructions and memory every few months, and remove anything that no longer applies.
Hands-on: the prompt doctor
Paste one of your weaker prompts into the assistant with this message:
Act as a prompt coach. Here is a prompt I used and the answer I got.
1. Diagnose which of these problems it has: missing context, vague
words, no format, no audience, too many tasks, no instruction for
missing information.
2. Rewrite the prompt to fix them.
3. Tell me which one change will make the biggest difference.
PROMPT:
---
[paste your prompt]
---
ANSWER I GOT:
---
[paste a short excerpt]
---Compare the rewritten prompt with your own diagnosis. Over time you will spot the problems before the coach does.
Measure your mistakes, then fix one
For one week, tag each disappointing answer with the mistake number that caused it. Most people find one or two numbers dominate. Fix those first; they are your personal highest-return habits.
Key takeaways
- Most poor results come from one-line prompts, missing context and vague feedback.
- Treat factual claims as leads to verify, especially numbers, sources, and health, legal or financial topics.
- Tell the AI what to do when information is missing, and never paste private data carelessly.
- Read everything before using it, and don't give up after one attempt.
Check your understanding
Quick questions to lock in the lesson. They don’t count towards your certificate.
Put it into practice
Review your last five AI conversations. Which of the ten mistakes did you make most? Rewrite one prompt to fix it.
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