The Family Meeting

Make the rules together, in one sitting. Keep it to about fifteen minutes so nobody drifts.

Ask one open question: "What is important to you about how we treat each other?" Write down every answer, even the silly ones. Then merge the overlaps until you land on a short, agreed list.

Post it where everyone passes daily, the fridge or a hallway wall. Now when a rule slips, you skip the lecture. Point and say: "We agreed to speak kindly. Let's try again." The poster enforces; you just hold the space.