“Most folks are about as happy as they make up their minds to be,” Abraham Lincoln observed more than a century ago. Scads of fancy research conducted since then shows this simple declaration to be true. Our circumstances are responsible for only about 10 percent of our mood, reminds Michelle DeAngelis, the founder and president of planetjoyride.com, a firm dedicated to teaching people how to create their own happiness. To rock the other 90 percent of your disposition, follow these seven mirth-making commandments.

New Rule #1

Recast problems as challenges

“Look for the value in the challenges you encounter” instead of cursing them, advises DeAngelis. This doesn’t mean that you take delight in the toilet, car and refrigerator going on the fritz the same day. But you’ll finesse the fixes much better if you think: Now I really get to give my multitasking skills a great road test!

New Rule #2

Love yourself

Shrug off a missed deadline or messy house by reminding yourself, “Nobody’s perfect.” Soap yourself up with a luxurious bath oil and murmur “I love you” to every extra inch on your thighs. Nourish your body by logging at least seven hours of sleep each night and by eating small, balanced meals every three hours. (Steady blood sugar keeps your mood buoyant, notes Robert Thayer, Ph.D., professor of psychology at California State University at Long Beach.)

Good self-care gladdens your spirit in two ways: It’s easier to feel cheerful when you’re rested and nourished, and you’re less likely to be resentful or snappy if you’ve been kind to yourself.

New Rule #3

Sweat off sadness

Studies show that exercise can be as effective as antidepressants for some people suffering from mild depression. “Ten minutes of brisk walking raises your energy level for two hours,” allowing you to tackle problems more optimistically, says Thayer. If your intent is to banish existing agita, work out for at least 35 minutes.

New Rule #4

Do the opposite

“What works for you 90 percent of the time kills you the other 10 percent of the time,” notes DeAngelis. If you’re always racing to get things done, practice relinquishing control by going off the clock and seeing where the day (and the kids!) takes you. If you’re the “rely on me!” family fixer, say “no” the next time you’re asked to play mediator, chauffeur or babysitter — and ask others to do you a good turn.

New Rule #5

Just say no to venting

The next time you catch yourself whining about someone or something, stop. Then ask yourself: Am I speaking to someone who can make a difference? Now, brainstorm how to approach a person who can. You might write to your boss, say, asking to be alerted about upcoming projects so as not to feel ambushed. Spending your “vent energy” on creative problem-solving will leave you feeling positive, empowered and content. “You’re not allowed to feel resentful if you haven’t spoken up,” DeAngelis points out.

New Rule #6

Let a smile be your Prozac

Scientists have a theory called the “facial feedback hypothesis.” That means a smile is not just the result of a good mood; it can also create one. Finding something — anything! — good to cite when asked “How are you?” is another way to put a twinkle in your temperament.

New Rule #7

Practice healthy detachment

Deciding that you can’t be happy unless you have a certain income, weigh a certain weight or live in a certain home is a guaranteed buzz killer. Never, ever let your contentment be contingent on others, or on a situation having a particular outcome. The fewer “musts” on your happiness list, the easier it is to be joyful, says DeAngelis.

Hard to disengage from a dream? Just ask yourself: Am I just going to stay miserable until I… (lose 20 lbs., marry a handsome millionaire)? Remind yourself that millions of women with far worse lives than yours opt for happiness and grace. And you can, too.