Use a telephoto lens. If you've got a digital or point-and-shoot camera, use as much zoom as you can get away with without distortion.
Shoot her a little off-center and compose closer-in. Use a slower speed and natural lighting, no flash (go with some daylight through a window to her side (off-camera of course)).
Take lots of pictures. There's nothing wrong with the smile and the dimples, but I'm not sure the "family photo" smile is the best for the material.
If you're like me, when you take pictures, whether of a babe in a bikini or a 75-year-old female professor, your job is to make her look gorgeous. You've got excellent material to work with; now go back in there and get some more practice.