1. Thou Shalt NOT Teach Patterns
"Many classes are taught by visiting show dancers,who are used to learning very complex choreographed dance sequences. To them it's the most natural thing in the world to learn & teach 'steps.'"
1 But the essence of tango is improvisation, not memorization of patterns.
2. Thou Shalt Teach Small Classes
As with any subject, large class size militates against individual connection between student and teacher, which is essential to learning. Otherwise put your class live online and teach millions at once.
3. Thou Shalt Not Leave Musicality for Later
Any sequence should be designed to the music, and since the music cannot be known in advance, no sequence should be taught at all. Instead, the student, especially the lead, should be given the skills to go where the music takes him and partner.