Courtesy

I always try to provide The Three Cee's:

Context, Continuity, Consistency

Customer-driven products don't have a coherent design. They lack .'conceptual integrity', a single-minded vision of a program which . is the most important ingredient to success.

Allen Cooper

Context

Know where you are and what you're doing

For example: You’re browsing documents or performing a function, such as document editing.

The introductory page should provide an explanatory overview of the operational elements and how they work.
Every major function (s.a. Create a New … or Edit) should have a set of directions.
When you enter or exit – and at appropriate points in the process – you should receive a synopsis of your activity.

Continuity

Embrace “sticky information”

The service should “remember” relevant information about your preferences, habits or even where you’ve been and what you’ve done.

The process is a thread of events
Design themes pervade the environment
Relevant information is “inherited” as you move through the workflow.
Pre-populate pages with appropriate choices and information.

Consistency

Behavior must be consistent

Employ harmony in terminology, color cues, layout conventions and design themes.

among functional areas or sections
within the pages themselves (i.e. between menubars and content)
within logical areas (i.e.continuity within the content documents)

Provide perspective. Keep track of things. Maintain a safe environment