The tip is automatically calculated for your room steward and wait staff and added to your charges, however you intend to pay them. It is roughly $10 per person, time number of days of cruising. However, the Cruise Director in his disembarkation speech suggested an additional $20 for your Waiter and $10 for the Room Steward if you felt them to be deserving. Of course, these were his guidelines and your own budgeting and personal feelings also determine the amount of additional tipping.
There were blank envelopes at the Information Desk counter which we used for this purpose...we handed our tip to our fabulous waiter with a personal expression of thanks and left and envelope for our Room Steward with a brief note of thanks, too.