I've heard this called "deep point of view" in other places, but I didn't learn it as such. 

First, Point of View is kind of like a camera. Should you choose first person or third-person limited as your POV, then you, as the writer, are holding the camera and looking at everything as if you are that character. You're doing the observing, the interacting. If someone other than your POV character is suddenly doing the interacting, the observing, the actions, then you have "broken" POV. This is perfectly acceptable when you switch scenes, to have one scene in one POV and another in another. Of course, everything is acceptable if it works. But generally, you would only have one POV per scene if you're writing third-person limited or first person. 

If you choose second person or omniscient, then you are still holding the camera, but you're not inside the character. You're waaay above the character, outside of them, watching everything from an external position. Viewpoint as filter is something you can use in first or third-person limited. If you are writing in second person or omniscient, another type of focal point is needed, such as theme. Often, omniscient novels are a sort of group pov where the author switches between points of view extremely often. 

You know you've broken POV (in first and third-limited) when you step away from the camera, outside of things you cannot see or know.  

                                                                     VIEWPOINT AS FILTER 
This is a technique that can be used in third-person limited as well as first person. 

When I was first learning some intermediate things in writing, I came upon a book called The Marshall Plan for Novel Writing by Evan Marshall. And he has a section in this book that really helped me to understand viewpoint writing. This is what he said:

Viewpoint writing makes all the decisions for you. Your viewpoint character is walking in a garden and sees some purple flowers. Should you give their name? If the viewpoint character knows their name, yes. If not, no; you would simply write something like:

"Masses of purple trumpetlike flowers crowded over the edge of the path."

Later, he says:

When you use viewpoint writing, your reader knows only what the character knows or is aware of at any given moment....

Whenever you're in doubt about what or how much to show at any given point, turn the question over to viewpoint writing. Would you describe your viewpoint character's appearance? Viewpoint writing says you wouldn't do so from that character's viewpoint, unless the character would have a specific reason to think about his own appearance....

This is a lesson I have to just keep learning. We writers--well, me anyway--create usable drafts and then try to force a pattern. We'll ask a friend what they think, and if they're a helpful friend, they'll say, "Yeah, I don't think so" and not let us get away with it. 

A couple days ago, my scene draft lacked emotion, so I created an intro (over 500 words of one) with all this power, and then just tried to force the two drafts together like some kind of sick matchmaker. And of course it didn't work. You can't force it like that when the ideas are based on different progressions. So instead of forcing a pattern that doesn't work, I'm looking at the next logical step in the scene's progression and seeing how I can work the info in rather than just blobbing two things together and going "good enough."

We all want things to be a certain way in our writing and in life. But sometimes, what we get is better than what we wanted anyway. We just need to let nature take its course.

As an editor, this is the biggest issue I see. As a reader, I see it and stop reading. 

The thing about writing is that you have something to say, right? Right? If you don't know what it is that you're trying to say, neither will the reader. Stay focused on one particular thing rather than jumping all around, and you have a better chance of keeping your reader's attention. Think about it this way: when someone is telling you a story face to face and they start rambling side facts and little things that have nothing to do with the story they're telling, doesn't your mind just kind of start to wander...like their mind is doing? Which means you're no longer interested. Stay focused.

There are a lot of different ways you can keep a scene focused. The standard way is scene-sequel, well described here: Writing the Perfect Scene

I use the Story Grid to help my work stay focused. (If you can't afford the book, their podcast is wonderful: Story Grid Podcast.)

If neither of these work for me, I ask myself one simple question: What's my point? Basically, what am I trying to say in this scene? If you find your work wandering, ask: what am I trying to say? Just don't be surprised if you discover the answer is, I have no idea.

Do you walk around thinking about your frizzy hair, height, eye color, etc? Exactly. So while you could give a descriptive dossier of your character, it will have no meaning, which means the reader won't care. But there is another option.

Have your characters react to each other. If you have one character say the other is a jerk while the other is doing something absolutely innocent, for example, that will say something much bigger about both of the characters. 

Think about it this way: if you only just met someone and they told you, "I'm the best person you're ever going to meet. I'm so nice," would you really believe them? Probably not. But if their friend walks up and tells you a story about how this guy saved someone's life once, your opinion of that person would likely go up. 

Consider how you can use various reactions to your benefit, particularly when your story starts. 

,This is a piece of advice I learned from Lisa Cron's Story Genius, which is in my top 5 best books on writing. (You really should buy it.) 

MISBELIEF. People carry beliefs about themselves, and they're not always true. The same can be said for characters. If you can define a character's misbelief about themselves, then it can drive an entire novel. For example, one of my own character's misbeliefs is that he isn't good enough. Things happened in the past to make him believe this. But through my story, he slowly comes to understand the truth about who he is. 

Although Story Genius talks about using this with the protagonist, I use this with every one of the characters in my novel. It's a powerful device that moves beyond mere "want" and "desire."

Basically, I'm busy. I've been back to exercising like a maniac on the rebounder--I should have just kept going the first time--and am going to start this Fall Hiking Spree my local community offers, the idea being to hike eight different trails in a couple of months in order to win things...or, if you're like me, because you would like to not fall over dead when trick or treating and doing random fun things with your 10 year old. I'm thinking it would make me look uncool.

I'm editing... a lot. Two new books should be released in the near future with a bit of my mark on them. One is a Viking romance that I'm convinced will be extremely popular. It's a great novel...and thank goodness it's part of a series. Another is a literary short story collection that really sucked me in with its depth and realism. Then there's a paranormal cozy with romantic elements that I will be editing in the near future and a thriller.... I've been really blessed this year to receive great work to edit and great clients!

I'm about 15,000 words away from finishing my WIP and then I'm going to work on a short story that's been orbiting in my brain. It's going to be a seriously productive year...or I'm going to be exhausted...or both. Likely both.