Thoughtful design is transparent and easy to understand, provides a preview, and helps users to easily correct their errors.| Nielsen Norman Group
Interactive elements must be at least 1cm × 1cm (0.4in × 0.4in) to support adequate selection time and prevent fat-finger errors.| Nielsen Norman Group
Direct-manipulation UIs support interaction with visible objects of interest via physical, reversible, incremental actions that receive immediate feedback.| Nielsen Norman Group
Break your text and multimedia content into smaller chunks to make it easier for users to understand and remember information.| Nielsen Norman Group
What is usability? How, when, and where can you improve it? Why should you care? Jakob Nielsen defines key usability concepts - give to your boss or anyone else who doesn't have much time, but needs to know basic usability facts.| Nielsen Norman Group
Modal dialogs interrupt users and demand an action. They are appropriate when user’s attention needs to be directed toward important information.| Nielsen Norman Group