Are you really talking about fine tuning, or are you asking about prompts?
If you’re asking about prompts, it’s often better to tell the model what to do in a specific scenario, rather than not doing something.
So the approach I would go for is this:
- identify the patterns that motivate the responses you’re trying to inhibit
- create prompt elements that are similar to that pattern (hooks) - and attach strong instructions to them about what to do in that case
- if you have trouble with the hooks not catching, it’s possible to reinforce the pattern with a global schema.
If you want to know more, in this thread we discuss how to inhibit the preachy baked-in behavior, but it should work just as well (or if not better) for your use-case.