Accepts that they can make mistakes.
Knows the material well.
To my child, the above are the most important points that he expects from a gifted teacher. He has had many disillusionments in his 3 years in school where he has seen that his teacher has lesser subject knowledge than him and was uninterested in learning enough of the subject to answer his valid questions and has shut him down because his question did not fall inside the scope of their lesson plans. He even asks me why his teachers do not have access to google or wikipedia so that they can read out the answers to him even if they do not know the subject very well.
So, for a really bright and curious child, a teacher who is a "subject matter expert" and who is willing to spend time to find out answers when they do not know them is very important. I like schools where they hire specialists to teach core subjects.
