Sometimes the stars align and you get a client who knows exactly what they want and is able to articulate their desires to you. This phenomenon is
Yes, the client is the authority on their product or service but you are the authority in your field. The person you are working with probably didn't get to their position by being a wallflower. These people smell fear. If you don't want to be used to mop the floor, you're going to have to be BOLD. Without a couple of years of therapy, how do you become bold?
The first element of boldness is preparedness. You can't fight for something that you don't understand. Being prepared is a life-long pursuit. You should be reading about your industry online, in magazines and books. Discuss your work with others in your field. Practice what you do constantly. In Malcolm Gladwell's new book, Outliers he says that successful people spend 10,000 hours on their craft before they reach any notoriety. 
To be prepared for the job you are working on, you have to listen to your clients. Oftentimes, we are so intent on thinking about our next statement that we don't listen to the other person. If you take the time to understand your client, you will be able to make better recommendations to them. You will know their personality and their company's personality.
Once you have made your decisions, explain to your client why. If your client doesn't understand the purpose, it is easy for them to strike it or treat it as trivial. It is also beneficial to give your clients a list of priorities. Clients rarely are able to do everything in the first round. Equipped with priorities, your clients will be able to make informed decisions.
