This is a pretty detailed video that illustrates the traditions and references you’ll see in Coco.
There are a couple of mistakes. (La Catrina started life as a political cartoon, rather than a representation of the Santa Muerte as the video implies; Ernesto De la Cruz is more heavily inspired in Infante rather than Negrete) but overall it’s full of useful information that will help you enjoy the movie even more.
Pixar’s Coco: The Traditions, Mythology & References You Should Know!