Service,Service,and more service. Helping someone buy clothing is a very intimate and integral part of being a "BOUTIQUE" What will set you apart from the pack is the level of knowledge you process, your ability to effectively communicate that knowledge to your client. I think in order to set yourself apart from online sellers is to be exactly opposite of what it is they have and have not to offer.I Find the more interesting I make my store by way of product mix I have to offer the longer the customer spends in your store. This gives you a unique opportunity to get to know who they are and what they like. Call this a social experiment with emphasis on social.