Without doubt, the best way to avoid plagiarism and adhere to copyright law is to give credit to others whose work you use or refer to. Doing so involves keeping careful records of your sources and documenting these sources using a style guide. When you document your sources, you create a path that your readers and other researchers can follow to understand how you derived your findings. If you fail to provide such a path, what you write may seem questionable, and your conclusions may appear suspicious.
Documentation acknowledges indebtedness to one's sources. It's expected that students, as well as writers, researchers, scholars, and scientists, declare such indebtedness.