I also tell shippers to disassemble the bar/stem/levers by removing completely from the brakes and frame and tying them over the top of the rear wheel if they have never shipped a bike before. In addition to what Tom offered, having padding between the frame and anything that could touch it is critical, as is immobilizing small parts and the front wheel. The front wheel axles will invariably tear open the outside of the box if not packed right, catch on something and rip open the side of the box, often moving the wheel around inside, with the resultant scrapes where the other end of the axle fits. Lots of zip ties is certainly a good start. Lou