I came across this passage recently in an article about autism and thought it made a great summary of some of the characteristics of any effective teacher:
Our respondents suggested that effective teachers were flexible but predictable. They had high expectations but were not too harsh or critical. They set clear rules but were still child centered. They allowed for differences but didn’t ignore similarities. They provided support without creating dependency. The teachers who made a difference for the respondents in this sample seemed to balance these tensions. In many ways, what makes a teacher effective for children with Asperger Syndrome are the same behaviors and characteristics that make a teacher effective with other children. However, the presence or absence of these characteristics may hold special significance for children with Asperger Syndrome.
Sciutto, M., Richwine, S., Mentrikoski, J., & Niedzwiecki, K. (2012). A Qualitative Analysis of the School Experiences of Students with Asperger Syndrome. Focus on Autism and Other Developmental Disabilities , 27 (3), 177-188.