Embrace Good Smells

"One of my simplest, cheapest (and calorie-free!) ways to boost your happiness every day is to embrace the good smells around you, whether that's your coffee, a grapefruit, clean laundry — even the hardware store or your own apartment building," says Rubin. "Your sense of smell can become dull over time, so if you simply focus on appreciating the scents around you, you can sharpen your awareness."

Rubin says that since starting to put her sense of smell to work, she's become a much bigger fan of perfume. "I'm in love with Lys Méditerranée and and En Passant by Frédéric Malle. I never used to be a 'perfume person,' but now I really appreciate beautifully crafted, simple scents."