Point of view is all about staying inside the mind of a specific character. This means that all descriptions, vocabulary, speech, and level of understanding should be within the scope of what that person knows.
For example, if your protagonist or other POV character is a teenager or child, they are going to see the world through that filter. Thus their comprehension and word choice should be appropriate for someone of that age. The came principle goes for an adult who is deemed highly intelligent. They will see the world according to their assumed education and experience and use more sophisticated speech patterns.
It’s essential to understand the concept of point of view (POV), which is the character through whom the story is being told. This can be one of the most difficult concepts for new writers to grasp.
The basic categories are single, multiple, and omniscient. Single is used for a first person narrative, but not always. It can also be used for a third person story that only goes into the protagonist’s head. Multiple will get into more than one person’s POV, but in separate sections or chapters. Omniscient gets into everyone’s throughout the story. This can be confusing and is also least effective in connecting your reader with your characters.
One way to check whether you’ve slipped out of a character’s viewpoint is to consider the subject scene as if it were written in first person. That will usually identify anything that doesn’t belong.
Bear in mind it can be confusing to the reader if you break viewpoint. Some slip-ups may go unnoticed, but others will throw them out of the story, the ultimate author faux pas.
Consider your story’s point of view carefully. If you really want the reader to relate to your protagonist, the story should be told through his or her eyes only, even if you’re using third person narrative. Avoid slipping into an omniscient viewpoint by including something your character couldn’t possibly know, such as what the other person is thinking, unless, of course, he’s telepathic. Instead, describe what your protagonist is seeing in the other’s expression and body language. Another way around this you can use occasionally is to preface it with, “He didn’t know it at the time, but….” Break point of view carefully, deliberately, and sparingly.