One smart thing Canada did is to accept a relatively well balanced portfolio of immigrants. By which I mean that we don't have an overwhelming minority group. Three cases to consider, Canada, Europe and USA.
In the USA immigration was (historically) composed of African immigrants. Currently they make up 15% of the US population. Increasingly they are being overshadowed by Latino-Americans, and I would expect this to cause issues in the future. There was always a sense of "us vs. them" when describing white/black relations though. There were always clear sides.
Likewise, in Europe, immigrants are from primarily Muslim areas. Just like in the USA, there is a undeniably "us vs. them" mindset in most European countries today. In a rather disturbing anecdote, when I was on exchange in Paris my host family described how if they saw a pure French person using a cross walk they would take their foot of the gas and apply the brake, If they saw a N. African crossing, they would just take their foot off the gas. Despite overall low to medium levels of immigration, that continent has some serious issues with integration.
Canada, though, is sitting relatively pretty. There was that Toronto terrorist thing a few years back, but I don't think there has been anything really contentious since the Christie Pitts riots way back when. We have one of the highest levels of immigration, yet few of the problems. In part, I think it is because we don't really have one ethnicity that is large enough to take a dominant role in society.