The wise man knows when to keep his mouth shut.
My friend "Simon" knows everything there is to know about hardware. If you want to to know the offset of a certain hinge by any manufacturer, Simon knows. In fact Simon knows so much he can't sell squat. Simon's problem is that he has to tell everyone everything.
When a person has becoome an expert in his craft, it is understandable that he wants to share all the options and ideas possible with new customers. Sharing knowledge is a great way to convince people to work with you. The key is to avoid overwhelming them with too many decisions and options.
Simon can't sell because he can't stop talking about everything he knows. Prospects avoid him after the first hour-long phone call. Everyone who meets Simon knows he is smart, they just wish he would stop trying so hard to prove it.
How many times have you met a very intelligent person who completely lacks social skills? Our egghead Simon is pure intelligence, but drives customers away with his lack of emotional understanding.
We all have a tendency to show off our knowledge, but when it comes to selling Keep It Simple Simon. The goal is to get the order first, then wow the customer with your ability, creativity and performance. The true test of your product knowledge is how well you listen to your customers needs. Create the product they desire and deliver on your promises.