If you truly wish to be happy, stop trying to manipulate life so that things go your way. This type of behavior is certain to create UN-happiness. There are two types of happiness; relative and absolute.
Relative happiness is based solely upon externals - money, cars, houses, girlfriend/boyfriend. Relative happiness is dependent on the material world to define you and is always certain to end. Money, cars, houses, etc. come and go. Even if you manage to hang on to it, you won't be taking it with you when you leave this earth.

Absolute happiness is never based on external conditions. It is based solely upon internal conditions and is not dependent upon material possessions for its survival.

The path to peace and serenity can be summed up in one word: Acceptance. When we learn to let go and realize that there really isn't much we have control over, acceptance becomes as natural as breathing. We set our intentions, take appropriate actions, get out of the way and allow the Universe to do the rest.