It's not until I found myself on the editing side of a novel that this has actually come up.
When I write a short it is generally from the perspective of a specific character. The novel, not so much. So I have now come across it. It has given me headaches, sure, but for the first time I'm looking at it, and I can already see applications.
So first off, what should perspective be?
Perspective (narrative point of view) is the position of the narrator of a story. Put simply it is the person whose shoulder you sit upon when hearing the story. Usually this is the hero.
In my example of shorts, I find (and it is only my opinion) that shorts generally have one POV. In a novel - unless one person is to be seen in each scene - perspective will change.
Think: Protagonist and Antagonist.
So what can we do with perspective?
Perspective can be used to bend a story. Think real-life for a moment. I am here. I am doing this. From another's point of view they may think me to be doing something else now. #Confusion.
Now if we POV the story:
"Mark will have left work by now. He'll be in Bar 46, down the High Street, on the corner. It's a seedy joint. Lot of old timers use it to pick up skirt. Young skirt. Too young, sometimes. That and the dealers. There are always dealers there."
Scum, aren't I? I'm in a bar, smoking weed and picking up jail bait.
But that's POV. That was all supposition. Look at the way it's worded. No 'has', only 'will have'
Now use it to toy with the reader. Change perceptions using perspective. Wend your trap. Spring it. Make the reader say, "No way."
'Til next time...
P.S. I think I'm getting the hang of this you know. But that's the next 'Writing Your First Novel'. Everything changes.