Look for someone who has a passion for teaching, someone who understands that it's not going to be easy from the teaching standpoint or from the student standpoint. Look for someone you can get along with that is not afraid to show their fallibility or to show that they might not have the answer immediately but will work with you to find the answer. It is a huge discovery process. Even the best athletes in the world show variations in technique and you need to learn around that and the instructor needs to be willing to spend enough time with you to figure out which of those variations are going to be best for you. You want someone you get along with that you like and that has an open mind and how they are going to teach you, not someone who says this is the only way that it can be done, that is the wrong approach for a sport.