Look up the Scoop method. Lots of video and discussion online. It greatly helped us when we first got our 5'er after years with a TT. 2nd tip was to learn to follow the 5'er in with the TV. Once the 5'er starts to turn where you want straighten the truck out. Don't be afraid of taking a few corrective passes to get it in the spot perfect. As others have noted it takes longer for the trailer to react to movement of the TV than with a TT.
While a spotter is essential, in our case a spotter doesn't direct me backing one bit. Their purpose is to make sure I'm not going to hit anything on the blind corner and to let me know if I've backed the trailer in far enough.