My experiences in teaching and training....

1. students are in widest variety of merits and aptitudes....
2. my focus is on individual development.... 
3. small batch of  4 to 6 is best....
4. delivery of quality inputs and guided practice must be costly....
5. costly teachers will help save money later....
6. expertise is a long journey of innovating , it's never everybody's cup of tea....
7. rapport building with the students is the primary job for a teacher to be a guru , in true sense....
8. commercialization is a social crime, if not effective for the deep learning and skills enhancement....
9. guru is much different from a teacher, as he is the most responsible person on the earth....