It'll run you more than $500, but check out my first grow journal (link is in my sig). It's done in a closet of similar size. Harrekin is right though. Read, read, read. There is so much knowledge in these forums and while it can be a pain to sort it all out, its worth it in the long run. There's a few good books on the subject too.
But it all comes down to experimentation. I'll tell you one great hint. As long as you follow the basics, you can't fail. You can make some pretty big mistakes and so long as you're on top of it and catch it early, these things rebound like crazy. The biggest mistake you can make is not trying.
Good luck, happy growing!