What's your work routine like?
Communicating with your contractor about the specifics of your project can be difficult enough. Do you really want the puce countertops? Should the roof be that slanted? With so many details to keep in mind, remember that you're going to have a person in or around your house for at least a few weeks (and perhaps months). And to them, your home is their workplace. So don't hesitate to ask them what kind of a colleague they are.
Having an understanding and expectation of a contractor's routine is vital to your own happiness. What time do they start working? Do they work until the project is finished, or will they be working on multiple projects at a time? It's also a good idea to inquire about what they do with leftover or waste materials. Will there be piles of timber in your backyard until April?
It's not unreasonable to ask the contractor beforehand if you have a schedule you'd like them to keep, and let them know that you'll be expecting regular progress reports. Once you have that schedule, take advice from the next page and get it in writing.