I obviously am pretty new, too; this was my first cruise. Wasn't sure how to put the link for where I got the travel folders; I tried it but since it may not work:
I got them at ebags dot com
Go to travel aids
Click on "Eagle Creek" and several options will be pictured. They are like an envelope; there is a hard board (that you don't pack) that you fold your clothes around, then put folded clothes in folder. When full (they hold a LOT) the sides fold up and velcro, then the top/bottom fold over and velcro shut. Just put the whole thing in your luggage, then I transferred mine to the drawers on the ship. I was a bit skeptical, but they worked extremely well for me.
I know I'm not an ultra-experienced cruiser, but everything is very fresh in my mind, so I don't mind sharing thoughts if you have any questions. I'm ready to book another (but DH may have other ideas...