I learned in elementary school about how to tell if a book was written in first person, second person or third person. It was a simple matter of pronouns.
“I,” “me," and “my,” or a "we/us" approach indicate a first person point of view. “You,” “yours,” or where I come from “ya’ll,” is indicative of a story written in the second person while “he,” “she,” “they” tells the reader the story is written in the third person.
For example, I can tell the story as if I am on the outside looking in. I can tell the story from several characters point of view. The best way to successfully do this is to use one perspective per scene.