THe best tip would be to go with an open mind. And have a great time. And like most ships on most lines, if you are going to the lunch beffett wait till 1:45 or so the lines will be shorter.
2004 Carnival Imagination Grand Cayman/O.R. Jamica
2006 Carnival Valor Eastern Caribbein
2008 Carnival Liberty Exotic W. Caribbein
2010 Carnival Spirit Mexican Rivera
2012 Carnival Freedom Exotic W. Caribbein