If You Were To Advise Your Son/daughter On Marriage, What W'd Be Your Greatest?

One of the reasons why I come here is because I desire to learn from people who are already in the 'business' of marriage. This is borne out of a dream to have an exceptional home; a marriage where I will smile all day because I am married; a marriage where the blessings of marriage surround me. I know I am not alone in this as there are a lot of young men like me who have such desires in their heart.

So if you are married and your opinion is being sought, it is because we don't wanna make mistakes. We want to know what works and what doesn't work. 

Supposing you have a son or daughter who desires to get married or is about to get married and you want that child's marriage to succeed, what will be your greatest advise to that child of yours?

Please tell stories where applicable.