Observe, listen, think about events, actions, and consequences, then make an informed decision about what is truly good, and what is truly NOT good.
It is not necessary or even advisable to PREACH to people. What will help them is to inspire them to THINK.
Life, the media, our peer groups, everything around us conspires to cause us to see things in certain ways. The only way to TRULY see is to find a way to take the scales off of our eyes and see what is really going on.