There are several ways of achieving happiness and one of them being, finding that special person who can give you the happiness, many a times its always that person you're in love with. Some people are very caring, loving and you'll just feel like you should always be around them. Other people believe that marriages make someone happy but not all marriages. The essential thing here is finding that one true love who can always be there for you.
Secondly, you can achieve happiness if you decide that you want to be happy from within yourself. Its just a matter of finding something from within which will give you some inner joy. Also, mingle out with people, air out your thoughts and try being an extrovert. This will surely work with time although the process is always gradual.