When you are wrapping a bundle of square wires, think of it as a plank, which has 4 square corners. Therefore whether wrapping with half-round or square wire, the wire wrapper needs to make a right angle at every corner, which keeps square wire 'on the square'. Using a good pair of flat nose pliers such as Swanstrom makes a major difference for a lot of folks.
The first DVD in my beginner series features my absolute favorite class for learning how to wrap with square half-hard wire (as well as how to easily straighten any wire, bundle and a great way to tape it all together.) The All Wire Unisex Bangle Bracelet will be able to help you in all of these areas.
Answer contributed by Dale "Cougar" Armstrong