You know the product inside and out and can adapt it to their needs. Your knowledge and expertise must be an added benefit to the product or service. Not overshadow it. There must always be a benefit linking your expertise and the product or service to the needs of your customer. If not here are some thoughts to help you become one.
Leaders are always well known.
At one time there was no Microsoft, Amazon or Ebay. Each of these companies created a positioning strategy against their competitors to become number one in their respective industries. Even though many copy cats have come along these companies maintain the perception that they are the experts. The companies above have one thing in common. They became well known.