A gentle answer turns away wrath, says Proverbs 15:1. 
In a family we don’t all agree. We don’t have to. In fact if everyone perpetually agreed, there would be need for concern. Healthy relationships are able to have differing opinions and continue to honor and respect each other.
* As Covey says, “Seek first to understand, then to be understood.” Most emotional issues dissipate once each party feels their heart has been heard.
* Listen to the other person first. Then repeat back what was said. “What I heard you say is …” A tremendous amount of problems are rooted in misunderstanding. If I heard something different from what the speaker was trying to convey, we can begin the process again. It is a continual mystery that we can speak the same language and frequently not fully grasp what another is communicating.
* After you have stated your position, ask, “What did you hear me say?” Many times I have asked that question and one of my children repeats back something completely different from what I said. Or what I thought I said. That’s good to know. It doesn’t matter whether the other person heard incorrectly or if I expressed myself in vague terms. Now I can use another description to better communicate.
* When two children are in opposition, have them work out a solution that is amiable for both.
* If a parent and a child differ, ask “how can we make this work?” However, there will be times when the parent will make the best decision based on family principles and additional factors.
The key is to go through this process as scripture advices, with a soft voice. Respectful and not interrupting, free from assumptions about what the other person meant or thinks. While we don’t agree about everything, we are on the same team and want what is best for each other. We are still a family.