If you're using third person and have several people starring as the focus character, there are things to remember. Don't change the focus character in the middle of a paragraph. Give each character enough room for the reader to know and be on their side. Often changing when the scene changes is effective.
Point of view belongs to the character who is viewing the scene. Be careful of what you revela. Most people don't give long descriptions of themselves as though looking in the mirror. Mary thought of her long black hair and her sweet smile. She thought of her blue eyes like the sky in summer. A character might use this kind of description to show other characters but unless very vain, not themselves.
Don't change the viewpoint character during a scene so many times you confuse the reader.