Tip your dining room waiter & bus boy as you leave your table and say your goodbyes the last night.
Tip your cabin steward the day before you disembark or leave it in an envelope on your dressing table.
Tip your wine steward the last night if you have used his services.
If you get room service tip when delivered,same as in a hotel.
Bar service-tip each time is the best way.
We tend to stop at the same bar/lounge and tip our favorites the last night,as was previously suggested.
Have a great cruise.