I do not recall receiving any advice about marriage from my parents. The only advice about raising children that I can recall my mother imparting was the suggestion to read only Dr. Spock. With the introduction of the Internet and blogging, my children can never make such a claim (unless they don’t read about my acquired wisdom...which is likely). This is not a definitive list, rather all I can think about at the moment.
Do not marry before 25. I have noticed that most people do not settle into their true personality until around that age. Marrying at an earlier can work, but people must be tolerant of change...or the two partners are really boring.
Live together for a few years to make sure it will work (no guarantee). The desire to have children is the only cogent reason for marrying...or maybe tax benefits.
Make sure that you are friends. This is more important than being lovers. The former is more difficult than the latter. Over time, one should increase, while the other fades.
Agree on three things: religion, politics, and child-raising.
Bad news does not get better with age, so share information.
Some dishonesty is necessary, especially when dealing with female weight, hair, looks, and fashion choices.
Disloyalty is unforgiveable...and completely unnecessary if you followed the above advice. One does not cheat on friends.
Be consistent with children. Do not let a child (clever little beasts that they can be) play one parent off against the other. Children always shop around for the answer they want to hear (But, mommy/daddy said it’s okay...).
Dr. Spock still works...
And finally, I can confirm that the following cliche is true: a woman marry a man and thinks that she can change him, but is disappointed when he doesn't; a man marries a woman and is surprised when she changes.