There are a lot of different issues involved in figuring out if copyright requires you to seek permission (and often, pay a fee) for some use you'd like to make, or if copyright allows you to make the use without permission. The map below may help guide you through the thought process.
This guide does NOT answer the "Can I Use It?" question for you - no one but you can make that decision! It can help you learn about and remember the relevant copyright issues. Keep in mind that publicity, privacy, defamation, and other legal issues may sometimes be relevant to whether you can use existing works - the more individual people are identifiable in the work, the more likely some of these issues are to be relevant.