On Finding a Good Teacher (based on my experience with teachers of martial arts, meditation, and music)

Being a teacher and Being a practitioner are two completely different skills.  Many aspiring learners try to find a teacher who is a great practitioner - this of course makes sense because they want to learn the skill from someone who has that skill.  The problem is that some of the most skilled people are not great teachers.  They may have mastery over the subject/activity but they may have no skill at communicating how they got it or how to break it down into achievable steps.  Instead of looking for an expert in your field as a teacher, look for someone who is skilled in the field AND is skilled at seeing what you are looking to achieve and how to help you achieve it.  If you spend most of your lesson/class marveling at how good the teacher is, you should probably find a different teacher.  A great teacher will take you right to a learning edge (something you understand but haven't mastered yet) and will help you get over that edge.