Principles of UI Design

These are the most important principles of good UI Design

Access: "Good systems are usable--without help or instruction--by a user having knowledge and experience in the application domain but no experience with the system."

Efficacy: "Good systems do not interfere with or impede efficient use by a skilled user having substantial experience with the system."

Progression: “Good systems facilitate continuous advancement in knowledge, skill, and facility and accommodate progressive change in usage as the user gains experience with the system."

Support: “Good systems support the real work that users are trying to accomplish, making it easier, simpler, faster, or more fun.”

Context: “Good systems are suited to the conditions and environment of the actual operational context within which they are deployed.”

Visibility: Keep all needed options and materials for a given task visible without distracting the user with extraneous or redundant information. Instead of WYSIWYG, use WYSIWYN: What-You-See-Is-What-You-Need.

Feedback: Keep users informed of actions or interpretations, changes of state or condition, and errors or exceptions using clear, concise, and unambiguous language familiar to users.

Structure: Organize the user interface purposefully, in meaningful and useful ways that put related things together and separate unrelated things based on clear, consistent models that are apparent and recognizable to users.

Reuse: Reduce the need for users to rethink and remember by reusing internal and external components and behaviors, maintaining consistency with purpose rather than merely arbitrary consistency.

Tolerance: Be flexible and tolerant, preventing errors where possible by tolerating varied inputs and sequences and by interpreting all reasonable actions reasonably; reduce the cost of mistakes and misuse by allowing undoing and redoing.

Simplicity: Make simple, common tasks simple to do, communicating straightforwardly in the user's own language and providing good shortcuts that are meaningfully related to longer procedures.

Source: Web