I'm in Canada and building a website for the US...approach?

[MelcorDev]

Hi there - we already have a Canadian website for the company and we're building one for our American branch.  From an SEO perspective what is the best approach here? We have already purchased a .com domain and the company is branded a little different in the US than in Canada.  How do I tell Google that this site is American and should be served primarily to the American audience? Should I be tagging duplicate content with rel=canonical (for similar pages like the About us section for instance) or does that matter here? Hope you guys can help.  Thanks!