When working with youth, (or in any teaching environment) there are things that I believe are important to being successful:
1) doing what you love and being passionate about it-
“A leader recognizes that his attitude determines his altitude. He
knows full well that nothing is as contagious as enthusiasm, unless it
is a lack of enthusiasm. He carries others to accomplishment through
the sheer strength of his overwhelming desire to bring success to his
assignment. The leader who gets the job done is one who inspires
confidence, who motivates action, and who generates enthusiasm. You
will ever recognize his work—for it will be well done.” --Thomas S.
Monson, “Be Your Best Self” p. 118
2) loving the youth-
Joseph Smith: "When persons manifest the least kindness and love to me, O what power it has over my mind, while the opposite course has a tendency to harrow up all the harsh feelings and depress the human mind." (Daughters of My Kingdom, pg 23)
3) don't be afraid to be flamboyant (it can be a learned behavior to be silly again :)...)-I listened to a talk by Andrew Groft from the 2007 Forum, where he said that a key to great mentoring is to not be afraid to be human in front of the youth, make mistakes, and even do something crazy every once in a while. It helps let the youth's guard down, and makes you more approachable and real to them. I had learned very early how to keep myself guarded and controlled, so when I first heard this, I was skeptical..."Surely, I am not one of those type of teachers. I just couldn't do that!" Yet, I tried it. I came out, draped in silks during a class on Pythagoras, that famous flamboyant mathematician. I cannot tell you how foolish I felt! However, you could see the youth, first shocked, then amused, then relaxed...all because I had a few moments of being "weird" in front of them.
I have seen since then how much easier it is for them to connect with me, knowing that I will honestly admit my mistakes in front of them, not pretend to know more than I do (most of the time :)...), and be a little silly every once in a while.
4) be with them--I cannot over-emphasize the importance of this in being a meaningful mentor. Go to the activities outside of class with them. Get down on the floor and play the games with them. Come with your own inspirements. Stand around and talk to them during lunch. Avoid the adult tendency to gravitate to other adults. Sit by them, learn with them, share with them, play with them,...be near them, and it will be easier for them to come to you, connect with you, and trust you. Not only that, it is in those small, unplanned moments that you can see little glimpses into their souls and personalities that are difficult to gain in class time.
Of course, you must moderate this interaction with other responsibilities, but make the most of the time you are with them to be with them.