One of the keys in any business is the ability to create a differential advantage. A differential advantage is the thing or mix of things that cause customers to choose you over your competitors. It must be something that shows how different you are from everyone else. Having a differential advantage is vital in business and is becoming more important in the age of the web were customers can search between hundreds of customers very quickly.
Jonathan Fields has a great post about how important it is to be different, and gives some great ideas. If you can't answer the question, "How is my business different from anyone else?" then you need to read this article: