I've heard quite a few people saying that they don't have a good system for remembering twisted corners and flipped edges.
This is more a MBLD technique if you're using rooms or a story, but for the letter where the green or blue sticker needs to be flipped to the top or bottom, I just use that first letter for people's names, and put them in weird places up high or to the side, so I know they are the flipped/twisted pieces. E.g. Going past a closet they are cramped up on the top shelf or something. Lol
I've only just started using it so dunno if it will work for more cubes.