App design process
This section contains info about how app design can affect the usability of a device. Many of the principles described in this section aren't obvious, but all have emerged from everyday use. Together, these usability principles can help designers solve problems, simplify tasks for users, and take full advantage of the platform.
This section doesn't cover programmatic principles or proper use of controls and navigation. For info about these topics, see App page model for Windows Phone and Controls design guidelines for Windows Phone.
Touch interactions introduce new design considerations. Successful design on a touch device prompts users on how to accomplish tasks and adds branding to your app. The best apps guide users efficiently through tasks, creating a sense of fluidity.
The process of planning an app is performed through a combination of interaction design and visual design, carried out in an iterative manner. Interaction design refers to the taxonomy of behaviors, gestures, and responses you design into your app. Visual design brings those elements to life on the screen with color and original art. Both of these facets of design deserve careful thought and planning before programming begins. Plan both interaction and visual designs ahead of time by doing mockups, drawings, and wireframes, then begin development. For more info about prototyping, see Design the best app you can.
Visual design can add beauty and branding to the user experience; however, it should never distract from the content or muddle the navigation. A successful visual design for apps creates an experience that subtly prompts users where and how they should touch, drag, and flick objects. Plan your visual designs so that they help users understand how to interact with your app.
Just as you would when you design apps for any human-computer interface, strive to create an engaging visual design consisting of shapes, forms, colors, and controls that help guide users through tasks.
Whether you're an experienced app designer or someone just starting out, this guide will probably present information that's new to you. Some of it will ask you to reconsider assumptions and principles discovered on other platforms, because visual and interaction designs for quality modern apps are very different from those you encounter in traditional computing. Spend as much time as possible interacting with a Windows Phone or tablet device during planning; get a feel for the platform, and consider the apps that ship with the device to be paradigms that can help inform your design process.