POV - is basically who is telling the story.
This according to a blog at The Wild Rose Press. http://behindthegardengate.blogspot.com/
is why most manuscripts get rejected.
Because new authors jump from head to head, not staying with one person long enough for the reader to understand that person's emotions and feelings before they jump to someone else.
It confuses the reader and pulls them out of the best stories. Most authors try to write a scene in one person's POV. Then when they start the next scene they may switch to another person's POV.
The only time I tend to break this rule is if I'm writing a love scene. I might go for a page in herione's POV and then switch to the hero's POV. This way I can reveal both of their emotions.
There are of course many ways to tell a story. 1st person POV only uses one person through the whole book.
When choosing who is going to tell the story, ask who has the best chance of getting your message across?
Or who has the most to lose?
Hope this helped,