Imagine Point of View like a parrot with a camera tied to its leg. A magical camera that can record all five senses. (Did not invent POV Parrot, but I don’t remember where I first read about it. I’ve completely co-opted the metaphor.)
The POV Parrot is tied to the shoulder of the point of view character. It only sees/hears/feels what she does, and so only knows what she knows. It can’t see another character’s thoughts, or look back at the POV character and see her from the outside.
In first person, the POV Parrot is tied to the narrator for the whole book. In second person… Well, if you’re the type who writes in second person, you probably clicked away as soon as you read: “POV Parrot.”
In most third-person fiction, the POV Parrot is on one character’s shoulder at a time. Sometimes it stays there for the whole book; sometimes it may fly off to another character’s shoulder for a chapter or scene.
Third person omniscient is like letting the Parrot fly around the scene, taking in what it wants. It sees what everyone sees, but it feels more remote than having it on the shoulder of a particular character.
The thing about the POV Parrot, though, is that if you send it flying from one shoulder to another too often, it gets worn out, and your reader may get dizzy from the spinning of the camera.
Think about those ‘documentary style’ movies where the camera bounces all around. It can make you nauseated after a short time. Even omniscient storytelling, the camera may see all, but it focuses on one character at a time so we don’t get dizzy, and we know what’s important.
Not everyone gets the POV Parrot. It plays favorites.
The POV Parrot belongs to your hero--the person who is moving forward the story, who has the most at stake. It may follow other characters around, or perch on their shoulders for while, but only when they are doing things that are related to what the hero is trying to do, helping or in the case of the antagonist, hindering.
Good luck taming the POV Parrot. Remember that its camera is how the reader experiences the story, so treat it well, and it will be a faithful friend.