Tommyjoking is exactly right.
     I have been welding a little over 10 years and running my own business for 6. Started in a structural/fab shop then worked in a stainless Alum fab shop then went to mostly heavy equipment. I have a lot of varied experience and have been lucky enough to have been trained well by some of the best welders I ever seen, 2 of which were older Mare Island welders. When I decided to go on my own and eventually relocated my business to where I live now I wondered how I was going to make it.
     I first talked to rock quarry operators, heavy equip. operators, trucking companies etc. left business cards at local auto parts store. I had enough work to keep me busy for 3 years easy. I've had local welding shops ask me to some work for them at MY rate when they were too busy just so they didn't have to turn down a customer.  All my work is done as Tommy suggested and the customers always call back. Those that know what it takes to do the job right the first time won't complain that it takes more time. Or they will realize it when they first try joe schmo down the street because he's a little cheaper but his welds look like crap and the repair breaks in a week. Then they call you and see the difference in weld quality and it never breaks again.
     One more bit of advice, when a customer calls and asks for a repair and says I have a welder here you can use, still use your own welder. Half the reason they called you in the first place is because they probably already tried it with their welder, probably a hardwire MIG machine when the best course of action would be SMAW. I always tell them I will be bringing my service truck anyways so I will be using my welder. Never rely on some elses equipment.