Biggest mistake I see from new drivers is over steering , trying to go from lock to lock , losing it and being nowhere near . Until you get used to it try to get as straight as possible ( if there is room use it , you can also see in both mirrors throughout ) reverse slowly on engine tick over only , small adjustments of steering should be all that is needed . If you’re lucky enough to get a Volvo FH / FM they’re easy to reverse with good mirror set up , Mercedes are hard work especially the six leggers … best to raise the mid lift to limit wheel spin , something you don’t want while reversing . Good luck.