Create a life purpose
In his classic book Man's Search for Meaning, psycholgost Victor Frankle showed that prisoners in Nazi concentration camps during World War II who wanted to survive for a particular reason often lived longer than prisoners who had no concrete goal.
Purpose or meaning in our lives is crucial.
In fact, many happiness experts believe in a sense of meaning or purpose is the attribute most strongly associated with life satisfaction. Frankl even created a new type of psychology - known as Logotherapy - based around this theory.
Why are you alive? Develop a life mission statement - a simple paragraph that sums up your main aim in life. Post it up in your home and workplace, and work toward it daily. As you get clearer about and more committed to your life mission, your level of satisfaction will rise.