I have a similar one, but he is generally very postiive and happy and does not have too much anxiety but he can be defiant and struggles with impulse control, focus, etc. I agree with the sports suggetion too. My DS is the best when he has had the exact right amount of physical and mental stimulation each day. Figuring that out is sometimes the hard part.
I would also consider getting a full neuropsych eval, IQ testing, other issues (EF disorder, anxiety) preferable with someone that has experience with gifted kids that may have other exceptionalities. It may give you a better picture of exactly what is going on with her. I would also recommend Transforming the Difficult Child - it does work if you stick with it. Finally, Smart But Scattered is a great book for helping with the organization stuff - bringing stuff home, cleaning room, etc. Others here have suggested Late, Lost and Unprepared too.
