There are several time saving adroid mobile device keyboard shortcuts worth knowing.
Many Android smartphones have a physical keyboards which means it also has keyboard shortcuts. And these shortcuts are customizable. The picture on the left is what you see what you press the menu button once, and then press and hold it again. You briefly get a look at the keyboard shortcuts for the top-level menu items. Want to quickly open the notifications area? Hold the menu button and press "n." Menu+p gets you to the settings.
Better still you can set new keyboard shortcuts, based off the search button. Go to settings>applications>quick launch, and you can set new shortcuts, or reassign the ones that are already there. (And in the case of android Pro, remap the quick-launch hardware button on the right-hand side of the device.)