What most naturally follows?

How to be a good brother
Be respectful.
It's important to set an example for your siblings by always being respectful. Be respectful to them, of course, but you should also be respectful to your parents, your teachers, your friends, and even perfect strangers! Being respectful will help them a lot in life and if they learn it from someone they really respect, it will become a lifelong habit.
Don't talk back to your parents or teachers. Politely argue if problems come up but otherwise do what you're told and show your sibling how it's done.