I usually pack a little gift of some sort for each day on the ship for the cabin steward. This time I also packed a stack of notes to write appreciation messages on. For instance one had smiley faces, one said thank you, or just howdy etc. to place along with the gift.
Another thing that my husband and I always make a point to do is take time speak with them in person. It means a lot to them to let them know that we realize how hard that they work and that we appreciate everything that they do for us.
Just a bit of "Food For Thought"