How do I make a game for all mobile screens?

I made a game with the screen size of 854 x 480 size perfect for mobile motorola defy. But how do I run this game on every screen fullscreen without leave blanks. Already tried everything. I want the game to run on all phones that appear without a white piece.

Check out this Example

scirra.com/forum/multiple-resolutions-solid-example_topic50496.html

I could not do work