Re Cubes Practice, try drawing a net on a piece of paper (make it as difficult as you can), with various different cube nets, and then try drawing the 3 visible faces onto a 3d cube. You can cut the net out if you like to check your answers.
Once you get the way the cube fits together sorted you will have a good shot at it. It worked for me at Eurocontrol (though i thought the cube test was easier!)