First and foremost, outstanding teachers must enjoy being with students. That might be students in first grade or doctoral students in college, but if you don't enjoy being with students, you won't make a good teacher. Along with that, you must have a heart for teaching and learning, as well as the ability to present ideas and concepts to others in a way that they can understand them. You must also be able to present ideas in a variety of ways for students who have difficulty comprehending those ideas and concepts.
An outstanding teacher must be fair and able to relate to a wide variety of personalities, good reading, writing, and verbal communication skills, and the ability to organize lessons, materials, and the classroom. Of course, the outstanding teacher must have the ability to deal with a wide variety of discipline issues in a fair, calm, and composed manner.
Did you notice that I haven't mentioned education yet? Education is important because the teacher learns methods of teaching, discipline techniques, where to find and how to make their own materials, and much more while in college. But, if a teacher does not have the personal qualities and abilities of a teacher, he or she won't make a fair teacher, much less an outstanding one!