What steps can a person take to form up an opinion on the quality of a particular teacher, so that a person can home in on good value options like this? I have heard rough ideas, like to look at what famous students are coming from a professor, but how does one go about this fact-finding? For example, how would one go check out the excellence of the UNT viola teacher? My S is looking towards jazz bass, and we have some time to look, but I feel at a loss for how to figure out where all the hidden gems of instructors are.