Designing the interfaces For system

hi friends,
Now we are in final part of our project that is User Interface Design
Following are the some rules we have follow during the design activities.
Design activity includes the designing of the System Interfaces and User Interfaces. System interfaces handle inputs and outputs that require minimal human intervention. Whereas the User interfaces handles inputs that involve a system user directly. And User interfaces require the user interaction to create inputs and outputs. The user interfaces is everything the end user comes in contact with while using the system. To the end user of a system, the user interface is the system itself. It is fact that designing the user interface is to design the system. Therefore the user interface should be given more priority in early development of the system. The term human computer interaction (HCI) is generally used to refer the study of end users and interactions with computer. Visibility and AffordanceVisibility means that control should be visible so users know it is available. Andaffordance means that the appearance of that control should suggest its functionality.