There are a lot of things that make a good teacher. I strongly believe that teaching is a skill that need desire, improvement, humbling and adaptability.
A teacher with patience, strong knowledge but in a way that can explain to 'everyone', just combining the technical and/or informal explanations. Who understands that different people learn in a different way, so the approaches (if possible) have to be distinct. Well prepared and with a strong desire to really teach and make difference on the people's lives. Essentially, that is humble and not self centered, in order to treat in a fair and efficient way.
Teachers are extremely important, especially when they know (and not know) how to teach. Don't underestimate your ability to change drastically (for good) people's lives.