...pay attention to what users do, not what they say.

If your users have many questions, it's a failure of your primary site design. It becomes not so much customer support, as much as customer complaints.

Progressive disclosure defers advanced or rarely used features to a secondary screen, making applications easier to learn and less error-prone.

Even better than good error messages is a careful design which prevents a problem from occurring in the first place. Either eliminate error-prone conditions or check for them and present users with a confirmation option before they commit to the action.

Even the best designers produce successful products only if their designs solve the right problems. A wonderful interface to the wrong features will fail.

Usability rules the web. Simply stated, if the customer can't find a product, then he or she will not buy it.

Minimize the user's memory load by making objects, actions, and options visible. The user should not have to remember information from one part of the dialogue to another. Instructions for use of the system should be visible or easily retrievable whenever appropriate.