Happiness and misery are products of the mind and to be able to enjoy life one should cultivate and pursue right resolutions. How this can be done is explained in this book.
Anything that is secret and mysterious in these systems of yoga should be at once rejected. The best guide in life is strength. In religion, as in all other matters, discard everything that weakens you, have nothing to do with it.
-Swami Vivekananda