First, do no harm. And listen to your mother—turns out she was right. Always be nice—especially to the person you married. Even when he hijacks the remote and she forgets to check the oil in the car. Take a deep breath, keep your anger in check and make it a policy not to sweat the small stuff.

If you want to enjoy a long happy marriage, there should be more positives than negatives, says Dr. Linda Waite, a leading marriage authority, the Lucy Flower professor of sociology at the University of Chicago and author of The Case for Marriage: Why Married People are Happier, Healthier and Better Off Financially, (available at Amazon.com).

“Some research has shown that for every negative interaction—criticism, complaint—there should be five positives, for example.”

No two people ever achieve perfect compatibility. Minor differences and everyday conflicts are inevitable in any living arrangement. It seems that happily married people accept these mostly petty distinctions, however annoying, with a certain amount of equanimity, patience, affection and respect.

The existing differences aren’t the issue, say the experts—rather, the ways in which we manage the differences can make or break relationships.

Save the big guns for the important subjects—everything else, well, a sense of humor definitely helps, along with a facility for diffusing anger, which can do singular damage to a marriage when allowed to flare unchecked. Name-calling, insults, intolerance and overt displays of contempt erode marriage’s essential foundation of mutual caring and support.

Making genuine attempts to see the other guy’s point of view is critical, as is the necessity for compromise—something that both parties must put into practice on a regular basis.

In most marriages, it seems that there is a season—sometimes summer reigns, other times, it appears as if November will never end. Long-term studies suggest that couples frequently report fluctuations in levels of happiness within their marriage over the course of a lifetime—being unhappy today doesn’t preclude you being happy five years from now.

For many reasons, your union is worth fighting for. According to Dr. Waite, “…under most circumstances it’s better to be married than single.”

Research appears to support the notion that being in a lasting marriage is better for your physical and psychological well being and better for you economically.

So what are the active ingredients of a happy marriage and how can you express them in your own home?

“Say nice things to your spouse. Do nice things. Tell him or her you love her. Talk about your shared future,” recommends Dr. Waite.

Until Death:

Dave McNeely, long-time political editor and columnist for the American-Statesman in Austin and his wife Carole Kneeland, journalist and vice-president of news at KVUE TV in Texas, were married for 15 years, until Carole died of breast cancer in 1998. Kneeland’s integrity was legendary and just before her death her colleagues established the Carole Kneeland Endowment for Television Journalism (www.carolekneelandproject.org ) whose board of advisors include Linda Ellerbee, Walter Cronkite and Ted Koppel.

In tribute to his wife and “best friend,” McNeely has generously agreed to reveal some of the secrets of their marital happiness.

“Personally, Carole and I felt we had the best romance and marriage around. Over the years, we developed a few important rules for our relationship. I share them in hope that you might find them useful.”

• The Blue Helmet Rule: We’re on the same team, not competitors; let’s help each other. No need for raised voices, no need to belittle.
• The 60-60 Rule: Meeting each other halfway is 50-50. Let’s meet each other more than halfway: 60-60.
• To Whom Does It Matter Most Rule: If a disagreement arises, quickly find out to whom it matters most — and go with that person.
• Housework Rule: There are no “his” and “her” jobs; no one is helping someone else. The work around the house is a joint responsibility. If you can afford it, pay someone to do those things neither of you wants to.
• Money Rule: It doesn’t matter who makes the most money; it shouldn’t dictate who is the most valued in the relationship.
• Make Time for Each Other Rule: Never miss a chance to say, “I love you” or “Thank you.”
• You Don’t have to Eat Everything with the Same Spoon Rule: Cut each other some slack. There will be some things you want to do that your partner doesn’t — and vice versa. Be flexible.
• Always Look for an Opportunity to Celebrate Rule: Anniversaries, birthdays, victories. Let’s have fun.

“Carole Kneeland lived her life with love. For more than 15 years, I was blessed to live in the shadow of an angel.”