In my mind there are three pillars to successful music teaching: Content, Craft, and Concern.
The Content Area: Music
Perhaps you had a music teacher who was organized and dedicated, but didn't understand how to select repertoire, create a beautiful ensemble sound, or catch the little details that make music leap off the page. Teaching music requires a deep and unwavering commitment to serving the music. Any great teacher must be passionate and knowledgeable about their content area, and for us that is music. How much time do you spend researching repertoire? Is your ensemble balanced, and if not, why not? What weaknesses in your training need to be addressed? How expressive is your conducting? If I asked your students, what would they say about your musicianship?
The Craft: Pedagogy
We've all had a teacher who was knowledgeable about the content but didn't particularly care whether or not we learned anything. The stereotypical case is the performance major who picked up the education degree as a "fall back" position. Another example is the director who considers the ensemble as their own personal tool for professional achievement. Teaching is an honor, and in music education it is our job to teach students to take ownership of their own musicianship. It takes constant reflection, trust, research, and planning for the sake of one's students. Being a solid performer yourself is not enough. You must have command of ensemble techniques, a solid philosophical foundation, and a clear sense of whose musical experience is the priority... yours or theirs. If I asked your students, what would they say about your teaching?
The Concern: Students
I hear music education majors and younger teachers talking about whether or not students should like them. This is really a very simple issue. The question isn't whether students like you or dislike you. The question is whether students believe you are concerned about them. Notice I didn't say you should like them, I'm suggesting you need to care about them. If you genuinely care about your students, guess what? They will like you. It has nothing to do with being friends with them. It has everything to do with valuing them as individuals. Stop looking at an ensemble as a singular entity and take notice of the individuals who sit in front of you every day. What do you know about them? If I asked your students, what would they say about your concern for them...not as musicians, but as people?
These three areas show us why teaching is one of the most difficult professions. Being a content expert, mastering the craft, and caring for each and every student is an absolutely exhaustive endeavor. If you are truly pursuing the profession in this manner then you know you earn your salary each and every day. No one expects you to have the three C's in perfect balance. What is reasonable to expect is that you're always striving to improve. It's not any different than what we expect from our students.
Keep looking in the mirror, keep the faith, and never give up.