Like diazr2 said - turn sooner and less than you think you need.
The pivot point with a fifth wheel is literally in the middle of your truck bed. That point has to move sideways before the camper will start to turn. With a bumper pull, the pivot point is a foot behind the rear bumper and turns as soon as the front of the truck turns. You have to be patient.
My first trip to a VERY EASY storage lot parking job took me 50 minutes of angst, anger and woe. Now we're parked, unhitched and back in the truck to leave in 5 minutes. AND- I'm still relatively a novice at backing anything up.