advice for fathers

I was talking to a friend who's been in occupational ministry for over 23 years. He has two sons, aged 28 and 23 who are both loving God and serving the world. The older one is married and working for a non-profit, the other just got engaged. I asked him what advice he would give me to help me raise my son. He said a few things that were good, but after thinking about it a bit more, he gave me this: "Have a good marriage."