Perhaps you should look into starting up something within college - it's a great place to conduct discrete market research and you already know the basic demographics such as age, gender ratio (as a rough figure) so you've got a good position to start.
As for what to do, well there's alot. Perhaps you could start by selling things within college or it could be as simple as advertising a service/product your offering/selling outside of college, after all it's a place of education and people are eager to learn new things and often quite happy to help you out.
Is there any business tutor's you can speak to about this, perhaps they can set you on the right track. My main piece of advice is to do something you can manage easily; the last thing you want is for it to overwhelm you and put you in a position of college or business.
Good luck
Aspiring Young Entrepreneur
Before success will come failure.