# Know Your User or Client:
To begin, an understanding of the most important system or Web site component, the user or client, must be obtained. Understanding people and what they do is a critical and often difficult and undervalued process. The first step in the design process involves identifying people’s innate and learned characteristics, and understanding how they affect design.
# Understand the Business Function:
A system or Web site must achieve the business objectives for which it is designed. To do so requires an understanding of the goals of the system and the functions and tasks performed. Determining basic business functions, describing user activities through task analysis, understanding the user’s mental model, and developing a conceptual model of the system accomplish this. The system’s conceptual model must fit the user’s view of the tasks to be performed.
# Understand the Principles of Good Screen Design:
A well-designed screen must reflect the needs and capabilities of its users, be developed within the physical constraints imposed by the hardware on which it is displayed, and effectively utilize the capabilities of its controlling software.
# Select the Proper Device-Based Controls:
In addition to the keyboard, a system or Web site might offer the user a mouse, trackball, joystick, graphic tablet, touch screen, light pen, or some other similar device. Designer should identify the characteristics and capabilities of these various control mechanisms and provide the proper ones for users and their tasks.
# Choose the Proper Screen-Based Controls:
The designer is presented an array of screen-based controls to choose from. Selecting the right one for the user and the task is often difficult. But, as with device-based controls, making the right choice is critical to system success. A proper fit between user and control will lead to fast, accurate performance. A poor fit will result in lower productivity, more errors, and often user dissatisfaction.
# Write Clear Text and Messages:
Creating text and messages in a form the user wants and understands is absolutely necessary for system acceptance and success.
# Create Meaningful Graphics, Icons, and Images:
Graphics, including icons and images, are an integral part of design. Design guidelines for various types of graphics are presented. Icons are also described, including a discussion of what kinds of icons exist, what influences their usability, and how they should be designed so they are meaningful and recognizable.
# Organize and Layout Windows and Pages:
After determining all the components of a screen or page, the screen or page must be organized and its elements presented clearly and meaningfully. Proper presentation and organization will encourage the quick and accurate comprehension of information and the fastest possible execution of user tasks.
Wilbert O. Galitz, "The Essential Guide to User Interface Design", Wiley Computer Publishing, Second Edition