Getting out among people and engaging in conversation is the best solution. This can appear scary, but there is no painless solution. Personal fears need to be challenged.
Self help books are very much about cultivating a positive attitude in the reader. The danger is the reader may perceive the author as the source of hope, and not see the power lies within.
Bellow I have listed some of the books that have played a part in cultivating a positive thoughts in my life. I would be very interested in hearing about books or people who have helped you see the world is often a reflection of your thoughts.
Seeds of Hope
If your thinking is making you miserable because you can't see any good, here are some books that have helped me see the world in a better light.
The Magic of Thinking Big
Avoid believing things are better than they really are when you are on a peak, or worse than they really are when you are in a valley. Make reality your friend. - Peaks and Valley by Spencer Johnson, M.D
Peaks and Valleys
Life is not primarily a quest for pleasure, as Freud believed, or a quest for power, as Alfred Adler taught, but a quest for meaning. The greatest task for any person is to find meaning in his or her life. Frankl saw three possible sources for meaning: in work (doing something significant), in love (caring for another person), and in courage during difficult times. - Man's Search for Meaning, Victor Frankl.