Research your contractor. Ask them to give you names of the last few homes they built. Call those people and ask if you can talk to them or even view their new home. I don't know if they have them listed, but the BBB is probably a good place to check them out as well.
Someone makes a pretty good home design program, back when my parents added on to their house, they used 3D Home Architect from Sierra and layed it out themselves. The contractor used our plans for the project, so they must have been pretty good

. They saved a lot of money by having the contractor just build the shell, the house looked finished from the outside, but they did all the interior finishing (wiring, insulation, drywall, flooring, etc) themselves. My dad is pretty good at that kind of thing though, so if you're not, I wouldn't advise it. It's quite a project to undertake by yourself.