A common characteristic of happy people is that they feel they have control over their lives.  If you are unhappy, review your life to see where you feel things are out of control, then take action.  Too often, when we find ourselves in a difficult position, we withdraw and lick our wounds.  That's okay for a while, but doing something to solve the problem usually does more good.

Write a list of all the areas in your life in which you feel you don't have control.  Now write down three things you could do to improve each situation.

Perhaps you need to tell someone how you really feel.  Maybe you need to change direction or let something (or someone) go.  Taking action can be hard, but if the result increases your sense of control over your life, you are likely to feel much happier for it.