Focus on your fundamentals. Make sure that you learn about perspective, composition, anatomy, color theory, etc. Developing your own artistic voice is important, but you should understand the basics and build up from there.
As an added bonus, I think that there are a lot of good points in Neil Gaiman's University of the Arts' commencement address, "Make Good Art": https://www.youtube.com/watch?v=plWexCID-kA
Great choice. :D You actually don't have to go to art school to pursue art. There are plenty of great design programs at city/state colleges and in the meantime, you could finish all your required classes for a fraction of the price. I did that. I went to San Francisco City College and then transferred to San Jose State University. If price is an issue, this might be a better route. Good luck!
Work hard, sketch, paint, draw, study.
These are the basics if you want something. I'm a working artist, but I am yet as successful as I would like to be. I continue trying different things, drawing different ways, making art and crafts that stratify the creator in me while I wait for someone to ask for a personal piece or people to buy my work without fear. You work the crowd knowing what will sale, what could sale, and what you want to sell and make.