Companies to haul for?

i am a company out of north west Ohio currently operating a fleet of 6 trucks. We are currently contracted on with Keller trucking, pulling their trailers and freight. We are looking to purchase our own trailers and find our own freight. Does anyone have an idea of what good companies are out there to contact to haul their freight? I really don't even know where to start. We will be strictly dry van and operating one step deck trailer.