Remember to pack your documents/passport in your carryon and keep it with you to show as you enter the port (not in the trunk of the cab like we almost did! Good thing that bag wouldn't fit in the trunk!
Have a pakcing list (there are many out there to use as a starting point, do a search). Check off things as you pack. Don't forget chargers for phone, camera, etc. If you use odd batteries for any gadgets, you might want a spare. Meds (always pack valuables in carryon).
Princess has self-serve laundromats. I can only use hypoallergenic soaps, so I do my own laundry. I bring a mesh laundry tote that folds up to nothing. Leakproof containers work well for my laundry soap, shampoo, etc. You can get these at www.containerstore.com