The devil is in the details. Think beyond your product or service and instead pay attention to your total customer's life cycle experience. After your focus groups, usability studies and whatever else you typically do, create a flow chart which shows the different ways your product is purchased, installed, used, supported and returned. But don't stop there. I believe marketing is the voice of the customer. So be the customer. Do everything yourself which is on the flow chart and I promise at least one detail will have escaped you.
Before Christmas I bought two pieces of jewelry from Overstock.com. They came in one small shipping envelope. Well the sizes weren't quite right so I attempted to return them. Problem is, whoever designed the return system never had enough imagination to think someone might want to return more than one item. That's right. You cannot return two items. Instead you have to print out 2 shipping labels, pay 2 shipping costs (and that doesn't include the fine print restocking fee of $4.95 per item). Customer service had no idea what to do either, because their system also could only handle one item. So I put both items in one package and mailed it back. This is going to be interesting. Maybe the system will crash.