How to tell story by portrait?
To tell a story you can use a lot of tricks.
Make your subject looking outside the field of view and focus on something unseen. It will intrigue a viewer.
For group portrait make your subjects looking within the frame. They could look at each other or at the same direction.
Give your subject room to look into. For this you have to put the face of your subject on the right or on the left edge of the frame and let him/her look across the image.
Experiment with lighting. You can get very powerful and dramatic portrait using directed light from only one side of the subject.
Take your picture candidly, when the subject does not aware this and acting naturally.
Position your camera a little lower than eye line of the subject. It is a good use for direct eye contact.
Use the rule of composition for your portraits. Position the subject in focal points of the rule of thirds.
Obscure part of your subject. Give a chance for viewer’s imagination to work.
Take a series of shorts using the continue shooting mode of a camera. It is a very handy tool for taking children photos.
Some object in hands of your subject can contribute in telling a story. For example, a camera is in hands of a photographer.
The Portrait Photographer http://portrait-photographer.blogspot.com/2009/03/composition.html
The Wonder of Light http://www.thewonderoflight.com/articles/?page_id=102