From my own experience, the one most valuable thing I've learned when backing is go SLOW. Doing so allows more time to correct or make adjustments without having to pull forward again.
My RV driveway at home is on my blind side. Once the right side of the RV starts to turn-in, I stop and adjust the passenger side mirror all the way out and I'm able to see. I do have a back-up camera but I have never embraced it as I just don't find it clear enough and it not wide angle enough.
As others have said it just takes practice.