Are you looking for malls or boutique stores? How expensive are you talking?
Barton Creek Mall has a lot of options for shopping in one place.
The Domain up North does too, lots of designer shops and higher end labels.
One of my favorites is Strut. There are several locations around the city, and they always have a great selection of new stuff.
Southpark Meadows has a ton of stores, but most of them are chains. Still, a lot of places to choose from. I have a ton of awesome dresses at the Ross in that area. about 5 years ago