It's very useful to get into the habit of coding resolution-independently. Set all UI element's positions by events, and always use some form of WindowWidth/Height or LayerLeft/Right/Bottom/Top in such a way as to not matter what the screen resolution is. For instance:
-> Set position of Sprite to WindowWidth/2, WindowHeight/2
This will ALWAYS, independent of screen resolution, make the sprite sit at the center of the user's screen.