To be kind, honest and have positive thoughts; to forgive those who harm us and treat everyone as a friend; to help those who are suffering and never to consider ourselves superior to anyone else: even if this advice seems rather simplistic, make the effort of seeing whether by following it you can find greater happiness.
I have found that the greatest degree of inner tranquility comes from the development of love and compassion. The more we care for the happiness of others, the greater is our own sense of well-being. Cultivating a close, warmhearted feeling for others automatically puts the mind at ease. It is the ultimate source of success in life.