I'd like to refer you to our website at BPlans, specifically the section on starting a business on that website, because it already contains a lot of material we've posted there, for free, about starting a business.
You're already on the right track -- you recognize that it starts with customers. In a professional service business the first customer is twice as hard to find as the second, and the second is twice as hard as the third. It takes patience.
Get that first customer, using every tool you can. Think about relationships from school, professors who might help, family contacts, whatever.
Once you've got the first customer, make them happy and keep them happy. The long-term secret is never lose a customer with bad work. They are so much harder to find than to keep, you have to make sure you never lose them. Most of this business is done by word of mouth, so you have to have happy customers and a lot of patience.
Do take a look at the website for more information on starting a business.