Useful Resources
Designing great applications and UI experiences can be tough, especially if you are new to it all. That's why we've put together a useful list of official user interface (UI) and user experience (UX) guidelines from the manufacturers.
Manufacturer Guidelines
The links below will help get you to get up to speed with the best practices and techniques for each platform and also contain many samples, tips, and descriptions of common mistakes.
Apple
Android
Windows
Wearables