How do we measure the usability of the system that we create? There are a number of observations that we can make that can help us.

Are people asking a lot of Questions?

Are Frequent Exasperation (the "Oh damn!") Responses Heard?

Are there many unnecessary and unproductive actions being performed?

Are there many elements on the screen that do not pertain to the user or to their particular task?

Do a number of people want to use it or not?

Eyeball fixation studies indicate that in looking at displays of information one’s eyes normally move first to the upper-left center of the display.

The eyes then travel in a clockwise direction around the display.

A study in 1984 found that visual targets located in the upper-left quadrant of the screen were found fastest and those in the lower right quadrant took longest to find.

Group and align screen controls and use line borders to help guide the users eyes in finding navigation elements.

Tab through information in logical order and place your command buttons at the end of the tab order.

Visually Pleasing Composition
A visually pleasing composition has the following qualities:

Balance

Symmetry

Regularity

Predictability

Sequentially

Economy

Unity

Proportion

Simplicity

Groupings

Create screen balance by providing an equal weight of screen elements, left, right, top and bottom.

Create symmetry by replication elements left and right of the screen’s center line.

Create screen regularity by establishing standard and consistently spaced horizontal and vertical alignment points.

Create predictability by being consistent and following conventional orders or arrangements.

Arrange elements to guide the eye through the screen in obvious, logical, rythmic, and efficient manner.

The eye tends to be attracted to:

A brighter element before one less bright.

Isolated elements before elements in a group.

Graphics before text.

Color before black and white.

Highly saturated colors before those less saturated.

Dark areas before light areas.

A big element before a small one.

An unusual shape before a usual one.

Big objects before little objects.

Provide economy by using as few styles, display techniques, and colors as possible.

The Less is More Principle

Create unity by:

Using similar sizes, shapes, or colors for related information.

Leaving less space between elements or a screen than the space left at the margins.

Create windows and groupings of data or text with aesthetically pleasing proportions.

Optimize the number of elements on a screen, within limits of clarity.

Minimize the alignment points, especially horizontal or columnar.

Provide standard grids of horizontal and vertical lines to position elements.

Provide functional groupings of associated elements.

Visually reinforce groupings:

Provide adequate separation between groupings through liberal use of white space.

Provide line borders around groups.

Consider using contrasting colors in the background.