Perhaps one of the best ways to deal with youth of this age is to teach them about heroes and conquerors, tell them about their stories and their attitudes, to create ambition in them. Also tell them about the reality that Muslims face, how their enemies plot against them and try to distract their youth with idle entertainment. Do not be too hard on them with regard to some things that are natural to them at this age, such as being concerned with how they look, but teach them the limits set by sharee’ah with regard to that.
I advise you to read the book al-Muraahiqoon by Dr. ‘Abd al-‘Azeez al-Nughaymishi.
May Allaah give you strength.