How do you stay warm in a Wisconsin winter?

There is a potential for me to get a job in Wisconsin. This job would be fairly physical and mostly outdoors. I might be in some unheated shelter sometimes, but could not always rely on that. Specifically, how do I dress to keep warm? Other tips?
While layers is certainly how I will be going, I also need to keep in mind that essentially, I will need to have one arm completely (or close) bare to complete my job. Trust me it will stay plenty warm!

Tagged as: job, layers