I often feel that if you show people respect they will return it. Some adults don't have respect for children. What I mean by this is that will often say one thing but do another thing. So they don't respect a child's intelligence enough. I would prefer to treat children as little people, giving them the benefit of the doubt that they can understand deeper subjects if one makes the effort to talk to them. Perhaps these days a lot of people are not giving enough time to talk to each other.
As to teaching children and teens, since I do not have children it is difficult for me to know all the different stages of teenage life, and also the power of being influenced by their peers, internet, the TVs, etc. However, I think that families who try to do things together, often stay together. Parents who spend more time with their children will often gain more respect from their children. Giving a child confidence in their ability is very important in the developmental years, and that again means teaching them ethics in a way that they can understand. But in order to teach anybody anything one has to be an example, because often people will pay more attention to the example than to the words. So if one is trying to teach a child compassion, one has to express compassion. If one is teaching a child respect, then one has to respect them as a little person and respect their level of intelligence and ability to understand.
Often adults don't give them enough time to explain their reasoning for doing things. When I was a teenager, my father and mother used to teach ethics to me and my siblings in a very interesting way, even though at the time I didn't even know they were teaching us their ethics. We used to have a lot of discussions at the dinner table at night. They would share their day with us and explain how they felt about certain things and their way of viewing the world. So their capacity to share their life with us was very important in teaching us ethics growing up. I am very thankful for that. As I said, I was not aware that was what they were doing, because they did it in a way that made us feel like a family and that made us feel closer to each other. They were willing to share their emotions, how they viewed things in life with us and we would listen and ask questions. That could be one way how families can share and teach people different ways of respect, etc.