like said above, make sure you're using the mirrors. I've tought a lot of people to back trailers (i'm a truck driver), but its a lot easier in person lol.
This may not help, since the bottom of the steering wheel didnt help. But if your trying to back straight up, you can try putting your hand at the top of the wheel. Watch your mirrors. If the trailer gets bigger in your passenger mirror, move your hand toward the passenger mirror. Move your hand toward the driver mirror if the trailer is getting bigger in that mirror.
The big thing is correcting the trailer before it is too far out of shape.
When your backing around a curve, start angling the trailer before you get to it. When your trailer is angled going around the curve, start straightening it out before your at the end of the curve.
Now if you're trying to turn the trailer with your hand at the top of the wheel, you'll have to remember to turn the opposite way you want to go...that may get confusing. That's how I do it, but you may just want to use that for straight backing. The main thing is just take your time and make sure you know your turning the right way before you move any farther. Even if you have to stop.
I see so many people want to stay moving so they can get backed in faster. But they start getting jacknifed, and over correct and it just turns into a big mess. Go so, stop if you need to. Backing a trailer is just making a series of corrections, so focus on making minor corrections early, instead of making harsh corrections when its too late. Don't fight the trailer.
Once you get the hang of it, when turning, you'll set the angle of the trailer, and then you'll basically just follow the trailer in, instead of forcing it