Where will she be staying and will she have access/time to do laundry?
Regardless, when I plan a trip I break the goodies into categories: Daywear, Nightwear,Underwear, Shoes,Cleaning goods, Maekeup, Medication, something to read. She will know if specialty clothing (getting dirty or going fancy) are required.
I plan as much mix and match to keep the count low. As it is, I usually have too much stuff with me and end up wearing the same thing over and over.