I had OP exact situation- went from F150 short bed and 2H BP to a 3500 GMC dually long bed with equispirit 2+1 GN 30.5’ hitch to bumper. Like go big or go home!
Before I sold the old rig, I drove the new one around empty for like 2 weeks. My property has a long windy reverse to park the trailers with many trees in the way, with old rig I could drive in straight and turn around, not so with the new rig.
Hub used to do all the parking with our old 6H but I forced myself to learn it with my new rig. First time it took me an hour and a lot of shouting at the hub LOL. Now I can do it in 10 min.
One thing I did struggle with for awhile- the “glutes” on the dually blocked the sides of the trailer so sometimes it was tough. I got out a lot to see where my sides were in relation to those damn trees haha
Same as everyone else has said- make a way wider swing than you think to turn right. Keep an eye on the back tires of your rig- I’ve definitely bumped up over the curb a few times with the back of the trailer 
One thing I bought that was worth every penny- a magnetic extendable attachment with a little plastic ball that goes right on the ball, extends up by about 2’, all you have to do is literally is reverse until the hitch knocks over the plastic ball, perfect hook up every time. Costs $25 on amazon. I gifted one to all my GN-hauling friends that Xmas!
One thing I still have not brought myself to do is pull in with that rig to a small gas station like my local down the road . I always have a full tank if I’m going local, fill up the night before, I know the “good” gas stations for places I go to a lot, and on a road trip I’d be using the trucker stops anyway.