By Paula Spencer, Caring.com

How to be happier and healthier for the rest of your life. We’d all like to make it to 100–but let’s face it, some people age a lot more gracefully than others. What’s the difference between someone who looks and feels vibrant in midlife and beyond–and someone who’s sick, sad, and already old?

Scientists are turning up some surprising key factors: approaches to attitude and lifestyle that not only add years to your life but add a better quality of life to your years.

“Studies on successful aging have shown that only one third of what predicts how well we age is controlled by genetics. About two thirds is based on our personal lifestyle choices — and is therefore under our control,” says psychiatrist Gary Small, director of the UCLA Center on Aging and author of The Longevity Bible (Hyperion).

Here are five longevity factors you can do something about.

1. Know what makes you truly happy
Why it matters: The Founding Fathers were right about the pursuit of happiness being as critical as life and liberty. Happiness boosts the immune system and helps tamp down stress. Involvement with activities, people, and experiences that bring joy and contentment also boost optimism and positive attitude, both of which are linked to longevity. And pursuing reasonable pleasures helps one live more fully in the moment, rather than dwelling on the past or suffering until some future happiness comes along (as in slogging through a job you hate in order to enjoy an annual two-week vacation).

The catch: Most people aren’t good at knowing what makes them happy, says University of Wisconsin geriatric psychiatrist Ken Robbins, a Caring.com senior medical editor who’s also board-certified in internal medicine.

What to try: Cultivate what psychologists call an “observing ego,” Robbins says. Pay extra-close attention to your mood for a few days. Jot down what’s happening during times when you feel particularly happy, as well as what circumstances drain you or trigger anxiety. Who are you with? What are you doing? What are you thinking about? How do you feel physically and why? How can you get more of those good feelings and minimize the less-good ones?

Don’t assume you know already; you risk falling back on cliches. Learn your personal triggers. “People often think that retiring and playing golf all day would make them happy, but when they do it, it’s not as great as they thought,” Robbins says.

Common happiness triggers: Laughter, music, touch, spirituality, exercise, good conversation.

2. Approach the “new” often
Why it matters: The brain loves novelty. Although different types of mental skills change with age–for example, mental computations slow–the brain never loses the ability to grow. And trying or learning new things builds new neural connections all through life

Maximize brain fitness and the body will follow in kind, says UCLA’s Small. Staying receptive to new ideas also fuels curiosity, open-mindedness, and creativity–traits linked to healthier aging. Unfortunately, habits also ossify with age, which can make us prone to dismiss new things or feel intimidated by them.

What to try: Work “mental aerobics” brain workouts into your day. You can buy software with puzzles to flex your brain or play games like Scrabble or Trivial Pursuit. Be sure to keep challenging yourself; move up to working harder Sunday crosswords or mastering an instrument with more complicated music.

Consciously pull out of familiar ruts: Listen to some music that became popular after your 20s and 30s, even if you don’t think you’ll enjoy it. Keep looking (and more important, feeling) contemporary by visiting a cosmetics counter for advice on fresher makeup, or try shopping with someone in their 20s or 30s to experiment with new looks in clothing or glasses. Travel to a new locale or to try a new experience (such as a dude ranch, eco-tour, or Elderhostel).

Explore adult-education classes at a community college or through your local parks and recreation department. Those over 65 can also find inexpensive, and often high-caliber, lifelong learning programs at local senior centers.