In my experience as a teacher, I would say that the most success I've had with teenagers was when I was able to show them that I trusted them to do a good job, and that I acknowledged that they could function on a higher level than a child. That doesn't mean I treated them the same as adults, because they're not. Let me give you an example:
When I was in high school, I was among the best young musicians in my state. I was twice ranked principal in the All State Orchestra, and I ended up going to one of the top music schools in the country. I won awards and scholarships and was praised by all, yada yada.
And yet, when I listen to recordings of myself play from that time, I am struck by two things -- one, that I was amazingly self assured, and two, that I sounded terrible. I couldn't hold a candle to any pro in any orchestra you could name. When you're a teenager, you suck at everything that is worth doing. You also suck at recognizing that fact, and are hormonally hard wired to not be able to examine your weaknesses. There are exceptions to the rule, always, but anyone in any kind of advisory capacity to a young person needs to recognize that and treat them accordingly. The last thing a kid who loves doing something needs is to be shown that they suck. Once they have a bit more skin in the game, the self examination can start.