This is a book devoted mainly to serving clients well, so you might be wondering why I've included this chapter. Why bother with colleagues? Isn't this book called The Art of Client Service?
The answer is, you will never be able to deliver great work if you don't have team members who are as fully invested in a client's success as you are. And one of the keys to achieving this begins the moment a colleague—someone new to the agency, or an incumbent switching from one account to another—becomes part of the team you serve on. Hardly a day goes by without one agency colleague walking in the door while another walks out.
Add to this the reality that agency turnover was nearly epidemic before the financial meltdowns of 2001 and 2008, and the need becomes acute. The inescapable fact is new folks need to be briefed on that account you will work on together.
There are two ways to approach this. The first is to focus on the product. Useful, to be sure, but in reality, price-of-entry stuff. You're expected to know the client's products and services, and should be deft at analyzing, summarizing, and synthesizing them for your colleagues.
Product knowledge will take you just so far. Where you really earn your paycheck is with your knowledge of and insight into the client people you serve, and the corporate culture they operate within.
By all means spend time on the client's products or services. But be sure to then spend more time on how your client contacts ...