Practice will improve your backing skills
Backing an 18-wheeler is just like backing anything else up. Remember learning how to parallel park a car? Anything easy or intuitive about that? We learn by doing. You may not FEEL like fooling around in an empty lot after driving all day, or first thing in the morning, but that is the best way to get comfortable going backwards, when there's no pressure. You might think you look like a fool blind-siding into an empty space when you have room to do it, and no danger of hitting something, but that's the time to work on that. Having a spotter is all well and good, but he is not responsible for the outcome of your actions. Get out and Look. A successful back is one where you don't hit anything. You don't get points for doing it fast and smooth. Nobody cares. You may be providing the other drivers and dock workers around you with some cheap entertainment. So what? They've all been there. Remove as many distractions as you can. Get off the phone. Turn the CB down or off, depending on whether somebody on the thing is actually being helpful or just busting your balls. A good set-up is worth more than a full set of mad backing skills. Take your time. Do it right. And remember, some days are just better than others. The best of us have days when we can't back for sour apples. Nobody knows why. Just remember to move slow, deliberate, and carefully. Ride the clutch if you have to. Clutch brakes are cheaper than fenders and mirrors. Watch out for the other guy. You'd be surprised how many drivers will try and squirt by somebody who can't see them. Be patient. Be courteous. Be safe.