READ: Portrait Photography Introduction
Light source and background
Here's a portrait of Kathleen from Tim_D's Flickr stream. It's one of the many portraits hosted on flickr.com. Notice how the light source is from the side of her face. This creates shadows and helps add depth to the image. You'll find the same technique was used in the painting of St. Philip. Also notice that Kathleen is not facing directly into the camera. She is turned about 45 degrees to one side. You'll also notice that the background in both images here is either blurred or is dark to focus the viewer towards the face. A busy background can detract from the subject so most portraits have soft backgrounds.