Avoid these common prompting mistakes that kill output quality:

1. Being vague: "Write something about marketing" → terrible
2. No format specified: AI guesses — often wrong
3. Giving up after one try: Always iterate
4. Wall of text: Use structure and tags
5. No role or context: AI has no frame of reference
6. Conflicting instructions: "Be brief but comprehensive" — which is it?
7. Asking multiple questions at once: Split into separate prompts
8. No audience specified: "Explain quantum physics" — to whom?
9. Accepting first draft: Good outputs take 2–3 iterations
10. Not providing examples: Show, don't just tell

Reference:

Prompt engineering best practices

https://docs.anthropic.com/en/docs/build-with-claude/prompt-engineering/overview