The three "R's" of successful mathematics teaching

Rigor
Students should do mathematical work that is challenging with feedback and any needed scaffolding.  Students should have the opportunity to demonstrate understanding in different ways. High expectations are key. 

Relevance
Students should see the power of mathematics and understand how mathematical knowledge is relevant to their current and future lives. 

Relationships
When students know that their teacher believes in them, cares about them, and wants them to succeed it makes all the difference.