Hi dee123.. welcome to cruise chat!
As you can imagine, there are so many things to say and discuss about cruising that your question is not answerable. There is so much we have an entire forum dedicated to answering questions. The good news is that cruising is also easy to do and if you just show up at the ship, you will still have a great time.
But, it is always handy to get information and "how to's" from people that have been there. I suggest you read through the various topics and get an idea for things and then you will have a better idea of what to ask as questions form in your mind.
Also, you might want to look in the General Cruise Chat area and read the FAQ. It has some typical subjects and answers.
Carnival Cruise Lines:
Fantasy 90, Celebration 95, Victory 05, Conquest 05, Spirit 6/06, Freedom 6/08, Holiday 7/08, Victory 6/09, Valor 9/09, Dream 6/10, Splendor 8/10,Conquest 8/11,Magic 11/11,Triumph 4/12,Spirit 7/12,Freedom 11/12, Triumph 2/13 - The fire cruise
NCL Dream October 2006, RCCL Mariner OTS June 2007