Numerous research studies confirm that the most important factor contributing to student success is the effectiveness of instruction. Though school quality is largely determined by teacher quality, that single factor is surprisingly difficult to improve. The well-chronicled and often-exaggerated reasons for this include veteran teachers resisting change, younger instructors lacking experience and improvement undermined in both groups by tenure's protection. However, another obstacle may hinder instructional growth with more certainty: Many educators view teaching as an art, in which best practices are elusive, hard to quantify and difficult to express. This is unfortunate. What the very best teachers do to produce the best results from students is not some unknowable mystery. Because it is unreasonable to expect excellence unless teachers know what excellence looks like, school leaders should identify, articulate and disseminate the habits of top-performing teachers. This article discusses five habits of highly effective teachers.