I’m a photographer and I’ve found that there are three basic skill of a good model. The most important skill is constantly knowing what your face looks like without the aid of a mirror as you’re cycling through expressions. The other two are finely tuned control of facial muscles and having a large repertoire of expressions. Being at ease with oneself is also very important, but more of a personality trait than skill. Beautiful people who make bad photos always make photos with the same bad trait: awkward stiffness.