The teacher is the most important aspect in educated the students in the classroom. It helps when the teacher is charismatic and has a passion to teach; after all they did choose to educate in a particular subject because of their love for that subject. Consistency is the key to a teacher's success. That means being consistent in communicating, grading, and most importantly the classroom management.
The public school system that we known and operate today has taken centuries of trial and error to create. The education system today has pulled strategies and methods from societies as old as pre-Mesopotamia and as recent as yesterday, not to say that education is constantly changing, but people are always trying to find new ways to improve upon the methods of educating the youth.
In preliterate societies schools did not exist. Children learned through the stories and songs that were told by their parents; these stories and songs were passed from one generation to the next for thousands of years. In these preliterate societies the skills of survival of the environment as well as the incoming attacks of surrounding villages. Once these skills were learned people in the village celebrated with dancing and music, this was their passage into adulthood.
One thing that is definitely worth noting is that every civilization had its own influence on the world without using the same methods or teaching the same people. The past societies did not even teach the same materials to their youth. The preliterate societies are an excellent example of that; they taught survival skills more than anything else. Another excellent example is the city-states of Greece, Athens and Sparta were neighbors and had two completely different methods of teaching as well as what was taught. The Athenians believed in teaching music, art, and all other sorts of culture. The Athenian goal was for their society to be filled with well-rounded persons. Spartans only taught military. They taught small groups of boys at a time until they were a certain age, then they were sent to train with one soldier until they were old enough to be a part of the Spartan military.