To make a good interface design, what are the primary rule that designer should follow.

Question

interface can include mobile apps, websites, databases. etc.

Answer 1

Designer should follow the 3 Mandel Golden rule 

Place the user in control - do not let the user feel that they do not have full access or control of your interface

Reduce user memory load - do not put too much onto a single view of your interface design

Keep the design consistent - make sure that the theme, settings, and view are all similar or consistent with one another