When an advanced player needs a good teacher, one would likely seek an experienced teacher, no? That experienced teacher has to have come from somewhere, right? When is a good time to start giving private lessons, and what age group one should initially try to teach? I'm going to be helping a close friend of mine with developing to be a decent trumpeter so she can play trumpet in her college marching band. I figure if I teach effectively to her (thanks to the countless notes I've taken from here, my own lessons, and some of my own thoughts and analogies), I could do some teaching at the middle school. I'm especially interested in the opinions of those who have a lot of teaching already under their belt, but I'll gladly take any advice given.