There isn't just a straight answer, so many ways to get business, and any successful business have most likely used many of those ways to get where they are...
In no particular order: cold calling, website, facebook, asking friends/relatives for work, ads on Craigslist (if it's in your area), set up at car shows, sports tourneys, put a sign on your front lawn,ask previouscurrent employers, offer to do things for free or cost to get your work out there. The list goes on and on and on... did I say on? Not to sound like a jerk or crass but there's no easy 1 thing you do and presto, you have a business. You have to work very hard to get the business and then work hard to make sure you keep it.
Go to Google and research: " how to market your small business free" and you'll find plenty of ways to get your name out there. Have cards made and tell everyone you know, everyone you meet, and everybody else that will listen about your new venture. Keep knocking on doors so to speak, do good work at reasonable price and do what you say, and the business will come. "build it and they will come" as the saying goes, you just have to build it.
Not trying to come down on ya or anything but it takes alot of hustle and determination to have a successful business.
Good Luck! Alan (22 years of working for myself doing it the right way, wrong way, and everything in between, but still kickin'" :-)