A resource that I refer back to periodically is a book called Character Building: A Guide for Parents and Teachers by David Isaacs. It outlines the general virtues that parents should be developing in their children at various ages.
From 13 to 15 Years Old
From age of thirteen to fifteen, it seems desirable, in view of the young person's greater awareness of his own intimacy, to insist especially on virtues linked with temperance, in the first place. The purpose behind this is to help him keep goodness in sight and not let his passions get out of control.
If we emphasized fortitude earlier on, we now come to harnessing that virtue to protect what is everyone's precious possession - his intimacy. By this I mean soul, sentiments, thoughts - not just physical intimacy. The virtues of modesty and moderation involve recognizing the value of what one possesses, so as then to make better use of it - in accordance with standards which are right and true.
What kinds of motivation can we offer children at this stage? I thing we have to give them reasons. We ourselves generally learned to behave by imitating our educators, but nowadays our children are not inclined to imitate us. They ask for reasons. ...[I]n connection with giving information to young people, I would dare to offer a recipe: information should be given by the three C's - clearly, concisely, and then changing the subject.
Apart from those virtues connected with temperance, it is good also to emphasize others which have to do with the person's privacy and with is relationships with others. That is why I stress sociability, friendship, respect, and patriotism. These four virtues presuppose being interested in one's own privacy and in the good of other people in a practical way. And it is here that the parents can make their biggest contribution. I refer to the guidance they give their children about how to channel their concern for others into practical acts of service. We should realize that the adolescent by his very nature is idealistic and also needs to have new experiences. If we parents fail to help him, then it is likely that outside influences will misguide him.
Simplicity, because an adolescent needs it if he is to act in accordance with his ideals and to be accepted for what he is.