Why prompts give generic answers
AI models fill every gap with the most average answer. A prompt like 'write a blog post about SEO' leaves out the audience, the goal, the tone, the length and the format, so the model guesses all of them.
Every detail you add removes a guess. That is most of what prompt engineering is.
The structure of a strong prompt
Strong prompts usually include a role or perspective, the task, the context the model cannot know, constraints such as length and tone, an example of good output when style matters, and the exact format you want back.
For system prompts and API use, add rules for edge cases and say what the model should do when information is missing.
Test and iterate
Run the improved prompt and a variation side by side. Keep what works, and turn the model's mistakes into explicit rules in the next version of the prompt.