Interface design and web design are closely related, but each has its own quirks. With interface design, your clients are going to be dealing with the interface themselves (as opposed to your client's customers) very often. The interface is powering their application or controlling their public website. So while it always helps to look attractive, usability is the main factor in a successful interface design. If your user interface can be explained once to a client and they instantly comprehend how to use the majority of features, then you've got a good interface design. If the interface itself makes it easy for the user to learn more about the system and to become more efficient at using the system effortlessly, then you've got a great interface.
Here are some of my great interface designs.
