Plagiarism is a tricky topic for many students, but two rules will help guide you:
1. When in doubt, cite it! There are some cases where you may not need to cite (e.g., common knowledge [explained later]), but plagiarism is a "better safe than sorry" situation. If you are not sure whether a source needs to be cited, go ahead and cite it!
2. Ask a librarian! Librarians are the citation/plagiarism experts and are happy to help you. This guide will explain some of the general concepts of plagiarism, but you might still be unsure of what to do in your particular case. Ask a librarian in person, by phone or via the chat box to the right.