The system should always keep users informed about what is going on, through appropriate feedback within reasonable time. The system should speak the users' language, with words, phrases and concepts familiar to the user, rather than system-oriented terms. Follow real-world conventions, making information appear in a natural and logical order.
Support undo and redo.
Consistency and standards Users should not have to wonder whether different words, situations, or actions mean the same thing. Error prevention Even better than good error messages is a careful design that prevents a problem from occurring in the first place. Recognition rather than recall Make 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.