Intuit recently published their style system called Harmony 101. Apart from a styleguide and a pattern library it also consists of these design principles to guide the way Intuit's software is designed.
1 Be simple, easy to use, and guiding
1. Establish a familial resemblance. Drive consistency and integration in the experience to keep the journey seamless, familiar, and harmonious.
2. Maintain user context by staying in place. Prioritize in-line or modal viewing and editing over new views or context-switching.
3. Guide the user where appropriate. Help users understand what to expect through progress charting and First Time Use tips. Provide useful views that guide toward common tasks.
Reduce cognitive burden, Helpful, Guiding, Consistent, One SBG, Clear, Clean, Simple, Functional
2 Design for the customer and instill confidence
1. Be trustworthy and helpful. Auto-fill commonly requested information for the customer and provide insights to help users improve their business financials.
2 .Imbue confidence. Avoid re-inventing the wheel; rely on familiar conventions when introducing users to new tasks. Don’t leave the user hanging; provide dynamic feedback where possible.
Confident, Approachable, Trustworthy, Soothing, Friendly, Warming
3 Establish modern and iconic ownable moments
1. Define a standard personality. Apply consistently across the Harmony suite of apps to provide unity and cohesion.
2. Celebrate unique tasks. Create ownable interactions and visual expressions that are a familial extension of the design language.
3. Project a voice. Define consistent use of voice to inject fun into the user experience.
4. Define ownable visualizations. Use visualizations to compliment data, channel personality and provide stickiness in the experience.
Clean, Typographic, Crafted, Differentiated, Unique, Capitalizes on Intuit Blue, Fun, Whimsical, Tactile
4 Celebrate data while respecting user & ....
Celebrate data while respecting user & device context
1. Be smart and appropriate for the task at hand. Use progressive disclosure of data and information, provide real-time feedback, and simplify required steps in task flows.
2. Understand the broader contexts of use. Minimize chrome and embellishments; design for user customization and personalization where appropriate.
Data is King, Context is Queen, Content over chrome, Insightful, Customized, Personalized