Top-half or bottom-half of steering wheel is how an old-timer taught me. I found it very helpful. If you're driving a straight truck use only the top half of the steering wheel. With a trailer, use the bottom half. Watch rear of truck or trailer in your mirrors, and turn the wheel in the direction you want it to go. You will want good full-length mirrors so you can see the top corners of a trailer, and the ground behind it also. Use the biggest convex mirrors you have room for. They're not much help for backing, but they are invaluable for lane-changing and for seeing your blind spots.
DwainG
DwainG