Some shortcuts…
Windows key + d: = Desktop
Windows key + f: = Search files
Alt+F4: = Closes a Windows 8 app (instead of moving your cursor to the top of the screen and swiping down)
Windows key + r: = Opens the Run dialog. You can type in the name of a program to launch it.
Windows key + x: = Gives a text menu with a lot of the old Start button's options, including Task Manager, Control Panel, Search and Run.
All shortcuts :
Windows 8 keyboard shortcuts