More often than not, critics complain about the actions of Christians, in which we are accused of not practicing what we preach. Because Christianity is a principled religion, putting the bar very high regarding morals, preaching the Gospel becomes a very heavy burden. The seeming ease in writing about morals is confounded by this burden. The message is not only directed to the reader but also to the writer. Otherwise, no one would write or preach about God's word. We'll all become paralyzed by this Christian's burden. As they say, less talk, less mistake; or perhaps no talk, no mistake. Jesus himself said: "The scribes and the Pharisees sit on Moses' seat; so practice and observe whatever they tell you, but not what they do; for they preach, but do not practice" (Mt 23.2-3). Obviously, although writing or talking is not the most effective way of teaching, a writer should not stop because he is not perfect in actually practicing what he says. As a principled religion, the intent to do good counts a lot even if we fail; this is the reason why Christ came, to call sinners. "Those who are well have no need of a physician, but those who are sick" (Mt 9.12).
What's the most effective way? Paraphrasing St. Francis on instructing his brothers: preach the Gospel, and if necessary use words; i.e., example is the best way. The most effective way of teaching children is by example. Parents who follow the Gospel, will have children who'll follow what's good and moral.
St. Thomas Aquinas wrote: "To teach in order to lead others to faith is the task of every preacher and of each believer." We as faithful should "impregnate culture and human works with a moral value" (Lumen Gentium 36.3). The task is difficult, but we have to start somewhere.