Knowing the correct strategies to reach students who are learning what the teacher is teaching, not just the content. 

The teacher must make the subject accessible to each student. 

Knowing the standards for the classroom and being able to teach using them. 

Knowing all of the resources you have available and using them effectively. 

Making sure your methods of teaching are affective for the students you are teaching.

Being able to analyze content; learning about the success of both you and your students.