What I like to do is take a word that I have always assumed I understood the definition
of, and hear alot in conversation or lectures.
I look that word up in the dictionary.
While reading that definition, I'll take one word I don't know the actual definition of
or one that seems vague to me, and look that one up, until I've ended up lookng up at
least 10 different words.
What you do is read a really good dictionary, and whenever you notice a word ending
with "ist" or "Ology" or something like that - something you didn't
know there was a word for, or a profession or area of study you didn't know existed.
You'll find out that you're not the only person who thinks about things like that, or
there wouldn't be a word for it.
So far, I've figured out I'm a cosmologist and philologist. A few years ago, I figured
out I was interested in quantum physics. I thought I just thought about things that people
would seem weird if I talked about them :}