Produce cross browser compatible code that degrades on older browsers.
Produce desktop and mobile-optimized & responsive interfaces.
Implement high quality interfaces
Proven real world experience with desktop / mobile application development
Obsessive about quality, including code quality and commenting
Knowledge of one or more Responsive Frameworks
Experience with browser testing and emulators
Should have the ability to analyze the requirements and come up with the most appropriate solution.
Should be able to independently design the solution for quality and reusability.
Have the ability to pick up any ad-hoc technology and continuous curiosity for new technologies on the horizon.
Should be a good communicator - both verbal and written communication.