One more comment for the OP.
After you have towed your camper a few more times, you will probably start consciously asking yourself every time you pull into a gas station (when you are NOT towing) ... "If I had the camper with me right now, how would I navigate this gas station."
It really does become part of your natural thinking, even when not towing.
I don't know how many times my wife and I have been out running around (in our car) and we'll end up in a parking lot, or down some road, and I've made the comment, "How in the world would we get the camper down this road?" Or "How in the world would we get the camper in THIS parking lot!" She laughs at me every time.
When you start thinking like this, even when not towing, I think you'll find navigating those gas stations much less threatening.
Edit:
I just though of 2 more things to add to my, already LONG list!
One: You really need to know the limitations of your rig? How tight will it turn, where are the blind spots under which conditions. How wide is it. Looking in the mirrors, what am I really seeing, judging my distance. In other words, the more experience you have with your camper, the more confident you become with it. What once appeared to be an impossible situation to maneuver with your rig, is now child's play. Know your vehicle and knowing it's limitations is everything!
Two: Knowing your own strengths and weaknesses when it comes to towing, and NOT being afraid to stretch your weakness, your fears, your doubts. In other words, the more difficult situations you find yourself in, the MORE you learn and grow. Is it painful! Oh yea! But only in the moment. Once you get through it, the next time, you're not near as afraid!