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

What we learned is money doesn't grow on trees.

A bad website is like a grumpy salesperson.

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.

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.

Consistency is one of the most powerful usability principles: when things always behave the same, users don't have to worry about what will happen. Instead, they know what will happen based on earlier experience.

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.