Turning of new iPad 4 / iPad mini as well as iPad 3 / iPad 2 and original iPad is in fact a straightforward procedure. Nevertheless there is some sequence you should follow to avoid any problem. To shut down your iconic tablet :
In many occasions turning OFF and ON your Apple tablet is the first action you need to take when working around its problems.
In some cases iPad may not be responsive to the Sleep-Wake button.
If this is a case try hard reset .