in order of appearance most likely the same as everywhere :

1)  have money

2) marry someone there

3) find a job there and they'll kick you out when that job is over

4) get a scholarship

5) live in a country that's under attack and flee

my native language is fluent sarcasm, not english, please dont let this be mis-understood : my message to the world

usually that's a question you would direct to your local canadian embassy who very likely has it on their website since its probably the most asked question they get.

google might know a bit more than musing on the subject

ohaio gosaimasssss