I like leaving the $10/day on the sail and sign because that way those that might get forgotton get something. And then cash at the moment of service is nice, Keeping a pocket with a few ones and fives works for me. A cook on the Glory at the Fish and Chips place knew we wanted some fish chowder and it wasn't ready yet. When he got it done he actually brought us a bowl. My daughter was dancer on that ship and with us at the time, it was extreamly important to her to get him a tip on the spot, We only had a dollar between us but she said having it right then meant a lot. I must say we always got a big smile at the fish and chips station after that.