And I have found it helpful to "set yourself up" for your intended position. To do that, lets say you are on a typical straight road with campsites on each side. Identify which side your spot is on as you approach. Lets say your spot is on the right (passenger side) of the road. I approach the site hugging the right side of the road. As the site is about to the front bumper of the vehicle, I start to angle the rig towards the opposite side of the road and keep pulling forward slowly. After the rear end of the RV (MH or trailer) is about 10' past the site, I want the RV to be on about a 30 to 45 degree angle to my site, basically blocking the whole road.
Now you are already half way through your turn before you ever start backing up. Now with your spotter standing on the corner of the site closest to you, start backing while watching the rear tires on your rig (lets say trailer) like Gary says. When the rear tires are at about the corner of the your site where your spotter is, now start cranking hard to get your RV to start moving into the site.
Just like Gary says, with a trailer you will turn the steering wheel all the way at first to get the trailer moving, then as the back end comes around, take about half of the turns out of the steering wheel. That will get the rig heading into about the center of your site.
Keep pulling back slowly, while your spotter is watching for obstructions like trees, picnic benches, and utilities. I like to put the trailer all the way back in as far as I can go, then make the adjustments in the site by going back and forth with smaller movements after you are in the site. Remember, you don't have to be perfectly in the site first time. Just get it in, and then adjust for straightening it or moving it left or right.
Always use a spotter, radios or phones are a good way to communicate, or clear, slow hand signals. And always tell the spotter, remember to look UP! Trees have a way of jumping out in your way when backing. As you practice more, the better you will get. Don't worry, we ALL had to learn to back up at one point, so don't be embarrassed while you learn.
We have a quarter acre empty lot next to the house. We normally keep the trailer next to the lot where the house is. I moved it to the far side of the empty lot a couple of weeks ago, over next to the neighbors Leyland Cypress trees. I followed her directions, and lined up where she directed me, and stopped where she said we were good. I got out of the truck and the front of the trailer was over towards our house by about 6'. She says "it looks straight with the trees to me". Needless to say, that doesn't help the problem any. She won't drive and let me guide her either, she insists I drive. When we go back to camphosting next month, the site we are assigned to is a really tight fit. There are two trees and a yield sign across the fairly narrow road from the site. With the slides and awning, I have about 6" side to side to be in due to trees on our site. The spare tire ends up about 1 1/2" from a tree in the back to keep the hitch a decent distance from the road. If I'm too far towards the driver's side, we can't open the slide without hitting the post that protects the pedestal, and more than 6" away from the pedestal with the slide open, we can't get the awning fully out. I think I will get my BIL to guide again this year. We have found out with the trees and sign across the road, it's easier to get it in as close as possible, unhook and line truck up from the other side to finish getting it oriented properly on the site. And that was with a truck 18" shorter than what I have now.
