You want somebody who knows what they're doing, of course, but all the education in the world won't mean a thing if you're not comfortable with the person. "Singing is like being naked," explains SJ. "If you don't feel comfortable with your teacher, you won't be able to let it out." Ask for an introductory lesson to see if you click with the instructor. If you don't, it's not a sin to look for somebody new.