You know how it’s one thing to teach children what to do, but it’s harder to teach how to have kavanah and joy. I think though that children learn through example. Therefore, if we Show kavanah and joy while practicing, we pass it to others.
Also, it’s important that we teach ‘why’ so they understand, and it’s meaningful to them, for example when they are in junior high and highschool years. Help them realize, it’s not just rules and laws, but a spiritual vehicle that helps us connect to Hashem.
Some individual youth might not feel it as much as others, and so it’s best to be patient and give them both structure and space.