We learn Canadian English, which is a blend of the two. For instance, we tend to follow the American for words like 'organization' (rather than the British 'organisation'), but we maintain the extra 'u' in words like 'colour' and 'favour'. My Canadian computer will tell me I'm spelling something wrong if I leave the u out of those words, but it's got the word 'organisation' underlined in red.
We also tend to follow the British conventions for some Latin words (amoeba rather than ameba, say) but the American for others (fetus rather than foetus). I have no idea why.
We tend to follow the American usage for punctuation. We use double quotation marks for dialogue, for example, instead of single ones ("Hi, my name's Elisabeth" vs 'Hi, my name's Elisabeth'). Having said that, I've been experimenting with the single quotation marks when I write on this forum.
However, we call punctuation marks by their English names -- for example, we say 'exclamation mark' and 'quotation mark' like the English, rather than the American 'exclamation point'. The only exception I can think of is the period, which in England is a 'full stop'.
My dictionary is an Oxford Illustrated, printed by the Oxford University Press (NY), and it lists the variant spellings, although generally the American spelling first.
In fact, now that I think about it, I'm not even sure if there is an official 'Canadian English' or if it's just a journalistic convention. I'm going to go look it up now!