The camera is a supplement of the human eyes; we follow whatever it focuses, whatever moves. The trick to mastering perspectives in cinema is knowing your character. Character perspective is a way of understanding which aids you to make visual choices in the scene. When you know your character, you know when you'll be objective or subjective; distant or intimate.
Since the cinematic camera is the audience's eye, one may want to empathize with the protagonist or the character in focus of the scene. Your angles, perspectives, framing, length of the lens, camera movement and editing rely heavily on this understanding.
Learn more about character perspectives with this study here.
Preview image was taken from the video.