Rule number one is to smile ocasionally. Everyone in canada will know that you foriegn if you are not a nice good natured person. A smile or grin every now and then is your first key to success in Canada.
Number two is about camoflauge. Canadians dress themselves in a wide variety of native clothing that ranges from styles from the Bay all the way to attire from Walmart. If you are an american visitor then you are most likely going to be okay if you just wear some normal clothes that dont draw too much attention to yourselves.
This next rule could be considered number one but I have put it at number three because I am kind of lazy. Know something about hockey. True hockey fans will know that you are lying through your teeth but the rest of the population will just smile and agree with you when you say that the leafs suck.
With those three rules in mind you are not just going to succeed in Canada but you are going to blend in nicely and be embraced by these warm and welcoming people.