I have long been fascinated by the catechetical methods of past ages. Rorate Caeli features the famous letter of St Francis Xavier in which he talks about his catechesis of the people of Malabar.
He used children to learn the catechism, and to teach it to others. The catechism and the commandments were the basis, a clear, simple, definitive and accessible message. I think our failure to convert, catechise and retain our faithful stems from the vagueness of message.