Hello, in order to improve performance, follow below guidelines:
keep things simple do not use box-shadow do not use text-shadow use opacity as little as possible use jQuery or other JS libraries as little as possible do not use CSS: animations and transitions and transforms do not use JS animations and fancy transitions limit number of AJAX calls decrease number of DOM elements remove unused code make sure your graphics are optimized for screen resolution (do not download big images and resize them in CSS / HTML)Unfortunately, there is no standard way of debugging on devices.