My other half's a fashion buyer, the usual business criteria apply. A good product, good quality reliable suppliers (the are agents that can help with this) and good buying prices. A good start to look at suppliers would be Turkey, India and China but this tends to depend on quantities and the product, even down to whether it's wool or cotton for example. If she is to trade from a shop it has to be in an appropriate location for the market. Obviously knowing her market is key. It's a good idea for her to get as much experience in the industry as possible first, in various roles. Good luck