Since it is extremely common for men to wear white shirts, this is a common problem. One way to avoid this is to use a light source off to the side of the camera instead of head on. Outdoor shadows from tree leaves or other objects can ruin a picture. Remember that what you are generally trying to do is to show the person or band clearly . A large image may clearly show that the shadows on a face are from a tree but, when reduced in size, the shadows start to appear as dirt.
Nobody wants to see a face of a dirty person.
Texture and tone are valuable to achieving a desired effect however, making an image softer by defocusing it or shooting through a softening filter results in an image which is difficult to reduce in size and maintaint detail. Another effect often used is to reduce the contrast to smoothen out an image. Once the contrast-reduced image is taken out of its context and put into a magazine or newspaper, these types of images often appear as improperly photographed. Leave a border around the subject. Try to avoid having the top of a person's head right at the edge of the image.