It's a lot like losing your virginity, you can get all kinds of advice and suggestions, but eventually you'll have to develop your own groove and do what works for you. Everyone sees and reacts a little differently, and every rig will have it's little quirks (at least in my personal experience), what works great for one person or unit might not be the best for the next. The suggestion of practicing in a parking lot is a fantastic one, running over or nudging a plastic cone is a lot easier on the trailer and pocket book than a road sign, car or tree. You can also make things progressively more difficult as you get a feel for the unit and handling, this way you can almost eliminate most of the stress and worry and concentrate on developing your driving skills.
I was employed way back in high school painting horse trailers, got all kinds of practice moving goosenecks around the shop and yard, started after class and at first I usually waited until most of the staff had left to move trailers. When you are just starting to learn, an audience is the last thing I wanted as I was nervous enough about moving a 30k unit. I actually set out empty 5 gallon paint cans and maneuvered around them. after a few weeks I was comfortable enough to wrangle the trailers from their position on the line, into the paint booth, and out in the yard with only 8" of clearance ( each side) around the overhead doors and the audience didn't bother me anymore.
After trying a couple times you will be able to develop a feel for your trailer, learning what works best for you and what doesn't. It's easy to try and type out what works best, but sometimes there is something lost in the translation, practice and experience will make it easier. Best thing is it's a big trailer, (kinda like a tractor) people generally take it in stride when you need a little more room and time to get things done.