From an article called "Effective Customer Consultant Relationships":
"As a customer, how can you get the most out of your consultants? As a consultant, how can you deliver what your customers really want? I have been on both sides of this relationship and experienced both successful and unsuccessful results. In this post, I will go through the typical aspects of these types of relationships and identify action items that I have used to forge effective and lasting customer consultant relationships for both parties." (from "Effective Customer Consultant Relationships")
If you are a tech consultant or are thinking of hiring one, this article has some excellent advice.