A teacher must do certain things to be effective but more importantly, a teacher must be. In God's eyes, being is more important than doing. The most effective method for teaching is one's life as a teacher. Attitudes and motivations of the teacher are extremely important in the teaching-learning process.
Inner qualities take precedence over outward appearance and activities.
God makes that rather clear in His Word. A good example is when He chose David as king over Israel. God led Samuel to Jesse's household to anoint the next king saying that it would be one of Jesse's sons. Surely, Samuel must have thought, the chosen one would be the eldest or the strongest or best-looking. The Lord does not look at the things man looks at.