Hi AussieGirl, welcome to Cruise-Chat! Congratulations on your up-coming cruise, just be warned, cruising is addictive
On most lines now, you can just do the auto-tipping. They add $10-$12/pp per day to your shipboard account. The amount varies from line to line, but it usually averages out around $10.50-$11.00/day per person. We also tip for room service, $2-$5 per delivery depending on the amount of food ordered. All sodas, alcoholic beverages, etc., bought from one of the bars will have an automatic 15-18% gratuity added to the bill. If someone gives you exceptional service, you can certainly give them extra. Tipping is always YOUR decision. If you prefer not to do the auto-tips, then go down to the purser's desk and have them removed before the end of your cruise, the best thing to do is go down the first evening. If you remove them, it is customary to tip your dining room waiter/assistant waiter, cabin steward, and your servers on deck. The maitre d', too. Again, this is up to you, totally.
We normally leave the auto-tips on, then give extra to those who give us excellent service. I tip in the casino, too. If I need to get my machine fixed, someone delivers a pay-out(which doesn't happen very often), or someone delivers a drink to me(which also doesn't happen very often since I play the machines and not the tables).
Again, tipping is NOT mandatory, it is to show appreciation for those who work so very hard for so little money. Often you will find your dining room waiter/assistant waiter at the buffet lines serving, cleaning tables, bringing around beverages, sweeping, mopping, etc. The crew are amazing and once you witness it, you'll understand what I'm saying. Be sure to smile and ask them about where they come from and their families. They're so very happy when they have people take an interest in them instead of griping at them.
Make sure you try the chocolate melting cake at least one time, it's wonderful!
Have a great cruise!