Good user experience and performance are crucial to any mobile application. In this session we will show you some of the important areas you should be attentive of when building your application: compatibility (handling multiple screen sizes, orientation), economy (use of alarms, passive location providers, using C2DM instead of server polling, using broadcast receivers), convenience (general UI tips for phones and tablets to improve user experience), and will show some techniques to build Android applications that are smooth, fast and responsive. Also, we will show some of the tools and techniques we use to track down and fix performance problems.