You ask. If your use is not permitted by a license, or one of the exceptions in the Copyright Act, you will need to ask for permission. The permission must come from the copyright owner so the first step is to identify who the copyright owner is and whether there is an organization that represents the owner. For published works, such as books and journal articles, the publisher or journal is usually the best place to start - they likely own copyright, or they can direct you to the correct rightsholder.
There are a number of copyright collectives which can give you permission (in the form of a license) on behalf of the copyright owner to use their work. So, for example, if you want to use music and your use does not fall within any of the Copyright Act’s exceptions, you may be able to obtain permission from copyright collectives such as SOCAN, Canadian Musical Reproduction Rights Agency (CMRRA) or Re:Sound that administer copyright in music.
But if the copyright owner is easily identifiable and locatable, it can sometimes be easier to contact them directly as many copyright owners will give permission to academic users without requiring payment. Usually you will be able to identify the owner somewhere on the work by looking for the copyright symbol ©, which should have the copyright owner’s name next to it. You will often find this at the beginning of a book, at the side of a photograph or at the bottom of a webpage. Once you’ve located the owner, simply email or write to him/her, explaining how and why you want to use the work and requesting permission. The permission should be in writing, though an email will suffice. It is not advisable to rely on verbal permission because there is no documentary evidence to prove what was agreed to between you and the copyright owner. You should also keep a record of who gave the permission, what was permitted, the date, and how to contact the person who gave the permission. Leave plenty of time for this process, since you can't control how quickly the copyright owner might respond.
Remember that copyright owners have the right to say no, charge a fee or impose conditions on the use of their work.
Feel free to contact the Copyright Office (firstname.lastname@example.org) with any questions you might have about obtaining copyright permissions.