2. He emphasizes precision in identifying the function of each Latin word. I would call his approach to translation both literal and sensible.
3. He thus approaches the language inductively, not by presenting grammatical forms as foremost in the learning process, not by means of a deductive approach that depresses and drives away too many potential Latin-lovers.
But what makes Foster a great teacher is his personality. Personality is a gift (gratia or charism). He's got it: enthusiasm, irreverence, not taking himself too seriously. He is the opposite of the dour, semi-neurotic, obsessive-perfectionist (and in Catholic terms, he is the opposite, in opinions and personality, of the typical neo-traditionalist). That gift of personality is what makes his teaching method effective. His personality is what connects the dots. There lies the mystery of great teachers: they combine sound strategies with personal magnetism. That's why great teachers are rare.