A colorful solution that even the least bright removal guy will understand.
To avoid confusion upon arrival to your new home, especially when moving a long distance, assign each room its own color that will be prominently displayed on the outside of the box. For example, an orange sticker can indicate the box should go in the kitchen, or a blue sticker designates bathroom items. Then place a matching sticker on the door to each room, which tells the movers where each box should go when they reach their destination. Also, check they're not colorblind.