Another aspect of happiness that you could focus on is whether happiness is genetic (inherited) or environmental. There have been numerous studies conducted that conclude that many parts of an individuals personality are inherited. In other words, if your mother or father were unhappy then you have a good chance of feeling the same way. On the hand, you could have learned how to be unhappy from their behavior. There have also been numerous studies conducted on twins and it was found that twins share many personality traits which supports the assumption that happiness may be genetic.
Unhappiness stems from other factors such as socio economic status, relations with others, and many other factors as well.
I would take an issue that is relevant to today's youth, and try to indicate how it impacts happiness. For example, today's youth are incredibly "plugged in," which means that they text, email, IM, Facebook, Tweet, and are in constant communication with one another. Does all of that communication increase their happiness? Does a technologically advanced world help or hinder in self-esteem? You could approach it from that angle. There are so many different products on the market these days that seem to promise happiness and contentment, so you could discuss that topic also. For example, most magazines for women are filled with beauty products; they are trying to make you feel like you need to go buy them to be beautiful. What impact do those magazines have on self-esteem and happiness? There is quite a bit of research in academic journals that would lend support for that thesis.
If you can think of something that impacts the happiness of you and your peers, that might give you an approach for this topic. Narrow it down to one particular thing that impacts happiness, and try discussing that. I hope that helps a bit; good luck!
There are so many directions you could go with interpreting and discussing happiness. One discussion topic that may interest you is- happiness and its relation to brain chemestry. It is physically impossible for us to be happy if our brain is not releasing the appropriate chemicals, namely neurotransmitters. Endorphins, dopamine, norepinephrin are just some of the feel good neurotransmitters.
Another direction you can take is looking at the support structure an individual has in measuring happiness. Does religious faith have an impact on happiness? How about being married or living close to relatives? I am attaching a link to a well written article on this subject.