Consistency Consistent with real life: in line with the process and logic of real life, and comply with languages and habits that the users are used to. Consistent within interface: all elements should be consistent, such as: design style, icons and texts, position of elements, etc. Feedback Operation feedback: enable the users to clearly perceive their operations by style updates and interactive effects. Visual feedback: reflect current state by updating or rearranging elements of the page. Efficiency Simplify the process: keep operating process simple and intuitive. Definite and clear: enunciate your intentions clearly so that the users can quickly understand and make decisions. Easy to identify: the interface should be straightforward, which helps the users to identify and frees them from memorizing and recalling. Controllability Decision making: giving advice about operations is acceptable, but do not make decisions for the users. Controlled consequences: users should be granted the freedom to operate, including canceling, aborting or terminating current operation.