Try not to use phrases like poses for the camera, shows off his/her (pearly whites, muscles, smile). They are unimaginative. Tell the reader information that is not readily apparent from looking at the picture. That means you have to find out if you don't know. This is getting harder and harder in recent years with the advent of selfies, snapchat, facebook and imaging gone wild. However, we as photographers with a very good telephoto lense can capture candid pictures. Try to use candids whenever possible and stay away when you can from posed pictures.