Very nice portrait. Mood - is also perfect! But light is a bit wrong i think ( i am not to much annoying?=)) Take a look here http://www.mvks.ru/Look/Studia/Oborudovanie/schema.htm
it`s not the best example, but now i cannot find more clearly.. You have to pay more attention how shadows fall on model - you can see under her nose and around her neck... Well, sorry for a long annoying=)) Good luck!!=))
I have little idea how did you get so great photo with the upper light. Though I don`t think that the photo could be better, but probably you would also try the standard studio setup - two sources of light placed about 30 - 45 degrees.
There is a little shadow under the lip. The high-quality film and probably scaner saved the picture.
(On the other hand, if you would do by the rules, you probably wouldn`t get so great portrait).
PS. Excusse my commnent - and certainly please don`t sue me - the girl is nice.