I saw this on Pinterest and still yet to try but if you put lotion ( I think it was) around your nails and then paint them and then wipe the lotion off around your nail the nail polish should come off your skin pretty easy. ( I hope that made sense)
It takes practice. I find that my right hand looks better than my left, and I'm right handed! I find that I paint slower on my right hand, so I don't mess up. But with my right hand, I know it's steadier and paint faster. Work hard!