LEARN as much as you can IN school AND inspection independently about the BUSINESS. (look at the recent Robin Thicke lawsuit and things like that). Get a solid musical foundation (composition, theory, etc) AND 'elect' biz related courses (management, accounting, planning, intellectual property, copyright, etc, etc.) Couple of basic (entertainment) law classes wouldn't hurt. The more you KNOW, the less likely you'll get used or just plain ripped-off. Also, ask yourself how much you're willing to put in and how much you're willing to give up to make this happen. Then, get yourself 'out there' - playing, accompanying, being seen and heard. Learn not to be afraid to say "No".
Sincere Best Wishes