A good older cousin doesn’t lecture. They just let you see how they handle things and you take notes.

Instruction invites resistance and demonstration does not, which is why you learn more from watching somebody slightly ahead of you than from being told. What gets copied is how a person handles things when they are not performing, how they talk to their parents, what they do when plans break, whether they are decent with nobody checking. Nobody announces any of it and everybody absorbs it.

If somebody younger is around you, assume they are watching rather than listening. Let them see you handle a small annoyance well. And find somebody a few years ahead whose way of handling things you would want to copy.