"Studies have shown that sustainable withdrawal rates are between 4 and 6 percent per year," says Armstrong. "Although it is important to make sure you make your money last over your lifetime, it is equally important to make sure you enjoy it as well."
4. Find a spouse — or at least a friend
Another finding of the Harvard study is the importance of stable marriages to happiness later in life. That may not bode well for the singles of the world, but finding some good friends may substitute in a pinch.
Kinderman says a lack of friends is a common theme she sees in seniors who are struggling through retirement. "They have a lack of socialization, a lack of a solid support system," she says.
For those who don't have friends and don't know where to find them, Kinderman suggests most areas have many resources for older individuals. From recreation centers to travel organizations, there may be many opportunities to meet like-minded peers in settings geared toward seniors.
5. Cultivate your sense of purpose
Finally, both Kinderman and Armstrong say they believe a strong sense of purpose is an important component to happy living in retirement.
"Be generous with your time, spirit, wisdom and energy," says Armstrong. "This stage of life is not about coasting, but about giving back to your family, the community and the next generation."
In addition, Kinderman says many older individuals may feel less than enthusiastic about their advancing age. However, she notes seniors should embrace the possibilities provided by their new stage of life.
"You are at a time in your life where you truly are your own boss," says Kinderman. "Don't look at retirement as an end. It is also this new amazing beginning."