How can I get my teen to take better care – daily showers, washing his hair, wearing deodorant – of his body?

This revolves around the teen's increased awareness of body image, as well as need for independence/rebellion. Focusing on this by the parent may be counterproductive. An occasional, gentle suggestion is perhaps as far as one should go. The vast majority of teenagers are well aware of their own appearance and that of their peers. And they maybe attempting to make their own individual statement in the context of clothes, hairstyle, etc. It is usually wiser to have made your own hygiene patterns apparent to your children at an earlier age, when perhaps there is more receptivity!