Things that will make you cheerful

Happiness levels are on the rise in adolescents, new research finds, but adults over age 30 are becoming less happy over time. Though people used to report greater happiness with age, that correlation vanished after 2010, study researcher Jean Twenge, a psychologist at the University of California, San Diego, told Live Science. The results may explain, or at least illuminate, a finding in another recent study - that the death rate for white Americans ages 45 to 54 is on the rise, even as death rates fall for other age groups.   
Scientific tips for living a happier life: Here are a few scientific tips to make your life happier. Go through it.
Don't Focus On It: Okay, you've got the animal shelter on speed-dial, and you're stocking up on stationary for thank-you notes. But be careful: A May 2011 study found that a hyper focus on happiness could paradoxically make people less happy. The study, published in the journal Emotion, found that women who valued happiness more or focused on it more exclusively had trouble actually achieving it. Perhaps these people set their happiness standards too high, Mauss said. Or they may be focusing on personal happiness at the expense of things that really make people happy, like relationships with friends and family.
Finding Happiness: If you're happy and you know it, what's your secret? Researchers have uncovered plenty of factors, from genes to personal characteristics to life choices that seem to coincide with happiness and its longer-lasting cousin, well-being. Here are a few you might have some control over.
Get Culture: Men who enjoy art, ballet and other cultural activities feel happier and healthier, according to a May 2011 study published in the Journal of Epidemiology. The result held even after researchers controlled for other happiness-influencing factors such as income. For men, physical activity, outdoor hobbies and volunteer work were also linked with happiness. The cheeriest women attended both church and sports events. Cause-and-effect isn't certain (maybe happier people take in more culture rather than the other way around), but the message is clear: It can't hurt to get out there.
Get a Pet: Pet owners are another group that tends toward greater happiness. A survey of pet-owners and non-pet-owners published in July 2011 online in the Journal of Personality and Social Psychology found that people who have dogs say their pets increase their self-esteem as well as their feelings of belonging and meaning. The research also found that pets had a similar ability as human friends to stave off feelings of rejection. In America, furry happiness boosters are all around: As of 2007, two-thirds of U.S. households had at least one pet.
Be Grateful: The power of positive thinking may really work, according to a 2010 paper reviewing 51 earlier studies on increasing happiness. The researchers, who detailed their work in the Journal of Clinical Psychology, found that people who get into the habit of writing down three good things that have happened to them every week show a significant rise in happiness. The review also found that study participants who wrote letters of gratitude to others reported a happiness boost that lasted for weeks. And no need for postage. Participants didn't even have to send the letters to get the boost though who knows, dropping that thank-you note in the mailbox might spread the joy around.
Cultivate Altruism: The same 2010 review found that giving back to others can pay happiness dividends. And a 2008 study published in the journal Science found that people who gives money away rather than spending it on themselves get a happiness boost.
Not only that, but people who volunteer for selfless reasons live longer, according to a study published in August 2011 in the journal Health Psychology. Altruism is even linked to stronger relationships: A 2006 study found that the most altruistic people were also the most likely to have happy marriages.
Get Nostalgic: Social and energetic, extroverts are also the happiest personality type. It's not easy to blossom from wallflower to center of the party, but you can steal an extrovert's happiness trick: Viewing the past through rose-colored glasses.