Count and test all of the leds that you will be using (512 for an 8x8x8) and bend either the cathode or the anode to the left with the other still in its original place just below the pin you are bending. Then bend the pin that is in the original position just a little so that there is a 90 degree tail on the bottom.
When all of the LEDs have been bent we will move on to the making of a Jig.
I found it easier to make my jig with 16 holes in a 4x4 square. This may seem like a bit of extra work but, by doing this you can insure that all of your sections of the cube are even.