That's really what we call it in writer lingo, POV. And if you screw up the POV that's how it will be marked in your pages.
Point of View -- Whose eyes are you behind? Whose skin are you in? I like what is called Deep Third Person POV. That is, when I speak of Alexa or Danith or T'Ash (and they are the hero/heroine) I say "She sighed, let her shoulders droop and trudged into her small house."
"I" is first person POV. Journals and Blogs are written in first person. There are advantages and disadvantages. With first person you have more immediacy and connection with the reader than even deep third person POV. Of course if "I" do something totally humiliating, you writhe and may put the book down. If "I" do something really disgusting and immoral, you may put the book down. On the other hand, with deep third POV, you can show other characters' thoughts and parts of the plot that "I" doesn't know.
We talked about POV on the Romance Divas website and I learned something about my friend, Linnea Sinclair, and about myself, too. First, Linnea said that when something isn't working for her, she checks to see whose POV she's writing in, and will change POVs.
I think I tried that once. Or twice. Usually I am solid in my POV, I know who's supposed to be talking, who I want to see the scene. I may move scenes around because I have too many in Lahsin's or Tinne's, or start the next scene for the same reason, but (knock on wood), I don't usually think too much about POV.
Keepers of the Flame, even though it was third person, was less deep than usual, mostly because I had two heroines. "Elizabeth and Bri looked around in wonder. Then Elizabeth choked as she saw the horse raise wings from its body." That is not as deep as my regular third person POV because I used Elizabeth's name in the second sentence. In deep POV I should have said, "Elizabeth and Bri looked around in wonder. Then SHE choked as she saw the horse raise its wings from its body." But this is confusing. The last female spoken of was Bri.
The fix I would use for this is to switch the names. Bri and Elizabeth looked around in wonder. Then she choked as she saw the horse raise its wings from its body." HOWEVER, a reader usually thinks of themself as the first person named in the sentence. So it's "I'm Bri." "Oh, no, I'm Elizabeth...." Any way you handle this, with two heroines (or heroes), it's going to be a little more distancing.
The general wisdom is to be in the POV of the person who is most affected by the scene. Who has the most emotions tied up in a scene.
I've also heard that in the "showing" not telling rule you might want to stick with the person less affected and watching the person who is most affected. This is interesting, and a good exercise but I don't know that I'd do it for anything but the exercise.
SHOW emotion don't tell it -- "She sighed, let her shoulders droop and trudged into her small house." There you have sighing, drooping and trudging. You can get an idea of her feelings. She's tired or sad or both (which you would get from previous and following sentences). You've been like that, right? Know what she's feeling? This has more emotional impact than "She was tired after the workday." (BTW, I was thinking of Danith in HeartMate here). HOWEVER, you will see that the SHOWING took more words and will take more sentences than the telling. And sometimes you HAVE to tell what people are feeling.
So that's longer than I anticipated and it's time for breakfast and to feed the cats.
May you be happy in your head today.