I've got two girls, now ages 12 and 10, and this will be their third cruise. We go with a bigger group, 13-16 family members, so there's always cousins and Grandma around -- which seems super fun on the cruise even though they see Grandma and their cousins at least one day a week! We take a book and an iPad each for the car ride to the port and occasional in-room entertainment. I pack a little bag of the same things I'd pick up for a plane ride - snacks we wouldn't normally indulge in, silly putty or Aaron's thinking putty, new gel pens and a small spiral-bound sketch pad, things to keep them occupied on the 3.5-hour ride to the port. They also LOVE a trip to Five Below to pick out one thing for the ride. $10 at most, and I know they'll like it.
We always eat dinner in the MDR and Sea Day Brunch is a family favorite. We grab whatever for lunch, but none of us are big buffet fans. We make sure to take advantage of things the ship offers like basketball on the highest deck, and mini golf. We do shows and games and whatnot. We try to sit in places that won't disturb others if we chose to walk out of the shows (bad/boring/too loud) or if the "family friendly" early comedy show isn't at all family friendly (Actually, that time, I WANTED everyone to know we were leaving!).
Keep clothes comfortable. Take an easy zip up hoodie for evenings. Cabin organization is key to preventing parental meltdowns.
My kids and their cousins LOVED the game room. They say that's their favorite part -- playing games they have at home with cousins they see all the time! 😉 😄