Here's a slick trick the pros use, and it's helped me out a lot. Use your mirrors for most of your backing, only look back out the window when absolutely necessary. Hold the steering wheel at the 6:00 position, and watch the corners or the trailer in the mirrors. When you want your trailer to move a particular direction, move the steering wheel the same way. For instance: I want the rear of the trailer to move toward the passenger side of the tow vehicle. Move the bottom of the steering wheel (a little!) toward the passenger's side, and watch the trailer move. Once the back end of the trailer is moving the right way, "follow" the trailer with the tow vehicle by counter-steering, making the tow vehicle follow the same path as the trailer. The trick is getting the initial movement in the right direction, and that's where knowing which way to move the bottom of the steering wheel comes in handy.
Jerry
