For example, did you know that the accepted style now for writing is to put all punctuation inside a quotation mark or bracket, even if only the latter part of the sentence uses these? That is just the beginning of what you should know if you are writing for business or pleasure.
The Canadian Press publishes their own style guide, geared toward the standard for Canadian newspapers. Called simply CP Style Book, it is available at the usual bookstore, as is The Globe and Mail's publication (The Globe and Mail Stylebook.) These are both good Canadian references and should be included in your style guide library. If you are writing for publication, you should have a good reference library and that library should include more than one style guide.
Probably one of the better know guides, The Elements of Style, was written by Strunk and White, for short. The authors’ full names are William Strunk Jr. and E.B. Little. Yes, that E.B. Little, author of Charlotte’s Web and Stuart Little. This book has been around since 1923 but don’t worry, it has constantly been updated.
The New York Times has its own self-named style guide and is worth purchasing as well. Just to add to the mix are two more American reference publications - the AP Stylebook and The Chicago Manual of Style.
For British reference, try Henry Watson Fowler's Dictionary of Modern English Usage and the Oxford Manual of Style by, reasonably, the Oxford University Press.
There are a plethora of style guides out there so don't rush out and buy them all - that is not necessary. You should, however, have a variety of guides to steer you through the differences inherent in the writings of each country. Also, if you are submitting works for publication, you don't want to take yourself out of consideration because you missed some of the idiosyncracies of a particular country's language use.