I say try doing different things. You might just be kind of bored with the things you do normally. Do something you don't normally do, or something that you've wanted to do but never got around to it. For example, sumali a sports team or a book club or drive to the beach. I think that if you look around enough, you'll find something that you really enjoy to do.
Don't expect that you'll be happy all the time. Despite what most people believe, happiness (the emotion) is not what people want to strive for. The type of happiness you want is the sort of fullness in your moral behavior (like helping other people out and such, depending on your motives). So to be happy, you just need to start helping people out (with your motive wanting to help them out) and trying to make others happy (even if it doesn't results to happiness of that person, the thought is what counts). Just don't be selfish, share your joy with people, help yourself rid of bad behavior (of course, its not possible to get rid of it all, just do the best you can), etc. Of course, this is all ethics stuff. Happiness as an emotion is just to find the stuff you like and do that. Things that makes you unhappy and isn't necessary to complete, you get rid of. All of this has to be within the limits of legality and good moral behavior.
Not everyone is happy all the time. But if u feel like being happy all the time my suggestion would be to think about all the things that God's ibingiay u. And be glad that He did. That'll make u happy.