How to find a goal in my life? How to figure out what I could enjoy doing?

I feel empty and I’m very unsatisfied with myself. I’m almost 30 and I still haven’t figured out what I could enjoy doing in my life. It might be anything simple, I don’t really care, I don’t need to be a great musician or scientist or other kind of hero. I just desire so much to fit in it, to enjoy it, to be good in it.

I desperately want to find out, but I don’t know how.

How can one find out where is his/her place? What do you think one might try?
How did you or someone you know eventually find out?
(sorry for my English, I’m not native speaker)
Thanks for any ideas.