Happiness is such a vague and ambiguous term.  In the basis of happiness, the definition states that the emotion that one has from contentment and satisfaction.  I am looking at the word satisfaction specifically.  As in, your satisfaction with yourself.  By being satisfied with yourself, you will start to understand why others are not satisfied and, down the road, develop ways to ensure your self satisfaction.  Many people have different things that keep them happy and content from the simple to the extravagant.  You want to make sure that the thing that makes you happy is simple to attain.  For example, it makes me happy when I see people smiling.  Its not that hard and generally speaking, you are around those many times throughout the day.  This keeps me happy and I am able to pay it forward.  Do some soul searching and find what makes you happy.