What does it take? - What credentials do you need?

What does it take to get into a top school like HBS, Wharton, Stanford for an MBA from Canada? What credentials do you need as an undergraduate student?

I'm trying to be realistic, and I know that from Canada, WS will be hard to break into. That's why I'm focusing more on building my credentials so I'll be a competitive applicant for the above mentioned schools.

However, with that being said I'm obviously going to give WS a shot from the undergraduate level and I don't know what school to choose. I'm getting mixed opinions between McGill and Ivey. Some say no one knows Western in the U.S., and McGill will give you an edge if you want to work in the US, some are saying Ivey is much better and is way more recognized in the street?

What do you guys have to say? To reiterate, I'm basically asking what credentials will I need to get into a top MBA school in the States and my second question is which Canadian program will give me the best chance to break into WS.

I also got into Queen's and Schulich, but they don't place that well in the U.S. so I'm ruling them out but feel free to comment on them too.

Thanks in advance.