~ The Absence of suspicion and resentment. Nursing a grudge is a major factor in unhappiness.
~ Not living in the past. An unwholesome preoccupation with old mistakes and failures leads to depression.
~ Not wasting time and energy fighting conditions, you cannot change. Cooperate with life, instead of trying to run away from it.
~ Force yourself to stay involved with the living world. Resist the temptation to withdraw and become reclusive during periods of emotional stress.
~ Refuse to indulge in self-pity when life hands you a raw deal. Accept the fact that nobody gets through life without some sorrow and misfortune.
~ Cultivate the old-fashioned virtues-love, humor, compassion, and loyalty.
~ Do not expect too much of yourself. When there is too wide a gap between self-expectation and your ability to meet the goals you have set, feelings of inadequacy are inevitable.
~ Find something bigger than yourself to believe in. Self-centered, egotistical people score lowest in any test for measuring happiness.
Source: Duke University Study on Happiness.