I always pack the day before a trip, sometimes the night before. My packing list is saved on my computer. The list contains everything I would want to take on every kind of trip I take, not just cruises. When it's time to pack for any kind of trip, I just print out the list and cross things off as I pack them, or that don't apply to this particular trip.
Of course, as I think of things I need, I add them to the general packing list. But why make lists each time you travel?
I also have on there things I need to remember to do, such as "arrange for mail and newspapers" and "set timers." These days I can't count on remembering everything on my own, especially when I'm excited about going on a trip.