Even before you position to load on the trailer, take a few minutes and use your lug wrench to tighten the lugs on all the trailer tires. Be sure you have a jack strong enough to lift the trailer and load in case of a flat, and check the spare trailer tires are in working order.
Even though the wiring harness was connected correctly, don't assume the trailer lights are all working. Get anyone behind the trailer to see if the turn signals, brake and parking lights, all work.
The side view mirrors were not designed to see around a trailer and load, so invest in a few blind-spot mirrors so you can increase your visibility on the road.
Schedule your vehicle's maintenance appointment at Norris Honda so we can inspect all the moving parts after your done towing.