Standards become culture when leaders apply them to themselves.

Standards applied unevenly are not standards, they are rules for other people, and everyone can tell the difference. Culture forms at the point where the person with the most latitude visibly holds themselves to the same thing. Nothing else establishes it as fast, and nothing else undermines it as fast.

Pick a standard you have set and check whether you actually meet it. Where you do not, either change your behaviour or drop the standard. The mismatch is more damaging than either.