Principles help guide designers and help provide consistency within their design.
There are two sets of design principles:
CARP - Stands for Contrast, Alignment, Reputation, and Proximity. Content is displayed in a format that is easy to read and understand. What is contrast about? Contrast in design involves the arrangement of opposite elements (light vs. dark colors, smooth vs. rough textures, large vs. small sizes) to create visual interest or draw attention to particular elements of a composition. How does repetition encompass consistency? Repetition involves using the same or similar elements throughout a design. This creates consistency, which helps in reinforcing an overall cohesive look, making it easier for the viewer to understand and predict the visual structure. What are the two functions of proximity? The two functions of proximity are to organize information and to create relationships between elements. Grouping related items close together allows the viewer to perceive them as a single cohesive group, which helps in organizing information and reducing visual clutter. ERBU - Stands for emphasis, rhythm, balance, and unity. Emphasis is the part of design that grabs the user's attention The point of the emphasis principle is to stand out and become the center of attention. Once the user's attention has been acquired, the rest of the interface and its design will come into play. Rhythm is a pattern within the interface design that continues throughout the entirety of the design. Rhythm can be described in three ways: regular, progressive, and flowing. Regular - a pattern that continues in equal intervals, one example being a black-and-white tiled floor Progressive - slowly change, like a color spectrum will change from one color to the opposite color on the spectrum Flowing - A continuous design; however, the shapes, colors, and path are slightly different Branding - A method for promoting an organization and the product the organization is known for.
Microsoft has 3 design principles:
Spacing and Positioning - Intelligent white space use gives your content room to breathe and is an essential design element and a powerful tool for effective web design improve the legibility of text create focus and emphasis give an impression of luxury Grouping - A Group contains several elements, such as text, icons, buttons, and shapes. There are multiple ways to group items, which include: boundary or enclosure - When a completed boundary encloses elements, they are perceived as a single unit—as a group proximity- where elements are grouped by spacing rather than enclosure. similarity - when various elements are similar in size, shape, or color to show an association connectedness - when elements are connected by a line or standard edge common fate - typically occurs in elements such as graphs. This occurs when elements appear to be moving in the same direction and are particularly important in animation. Intuitiveness - Intuitiveness is the most critical aspect of a great user experience. Intuitive designs lessen the need for explanation as the user knows what the controls do. Color-Coding - using green to indicate go or yes, and red meaning stop or no. 'Mental Bandwidth'—the amount of time it might take our mind to comprehend something—it uses. The lower the 'bandwidth' usage, the better your user experience. KISS (Keep It Short & Simple)
Simplicity should be a key goal in design. 
Unit 4: User Interface Design Principles
