6. Remember the 4-Minute Rule

You can predict how an evening with your partner will be based on the first four minutes of your time together, so make those minutes count! Bring flowers. Greet each other with a compliment. Ask questions about your partner's day. Smile; it'll make a difference.

Research shows that you must be nice to your partner to have a happy marriage. "The little things matter," social psychologist Susan Boon says. "You have to do nice things often. But it's harder to be nice when the heat is on, when you're really angry or when something has happened for the 15th time. Nevertheless, the balance must be heavily, heavily stacked in the positive to have a happy marriage."

Step 7: Open up to your partner