You can have the model close her eyes. Tell her on the count of three you'll shoot the shot. Ask her to open her eyes when you say 3. Then count, say 3, and then shoot. This often works.
Another obvious idea, is to put sunglasses on the model. You get some wonderful results and you can add all sorts of interesting refletions to the sunglasses after the fact.
By the way, I think the photo you posted has too much of a color cast to it. Did you augment or change the color in PS?
Here is an example of the 1-2-3 technique.
Cheers,
rfs