What makes a great teacher great? 

What do great teachers do?  What do their classrooms look like? 
Research helps us recognize and understand the effective practices that make great teachers great.  Theresearch-based article cited here describes excellent 4th grade teachers and their practices.  A team of researchers conducted two independent cross-case analyses of 12 teachers who participated in the study in order to identify key features of exemplary teaching.  Allington, Johnston, & Day discovered that great teaching is an "expert activity" that varies in each classroom, and so it does not fit into any "one-size-fits-all" instructional strategy.

Allington, D., Johnston, P., & Day, J. (2002). Exemplary fourth-grade teachers. Language Arts, 79 (6), 462-466.