This is really a personal preference. Some folks love going to Parrot Cay for a sit-down lunch, but we much prefer to head up to Deck 9 the first day.
Right when we board I usually have to sign up for something at Guest Services (Martini or Wine tastings usually) and book Palo tea or brunch if I wasn't able to get it online. Last time I also stopped by the Vista Spa line to change the time of my Alone Time treatment I couldn't do online. All those things happen on Deck 3 and go really fast if you are on the ship early. I was done with everything within 15 minutes and got everything I wanted.
Then we go straight to Deck 9. We're usually hungry and stop at a table outside to leave our carry-ons. One of the kids usually hang out with the stuff and I will get their first plate for them. Both times we've done this we were among the first in line for the buffet and didn't have to wait long at all.
Then the adults can eat liesurely while the kids scarf down their food and head to the pool. They wear their suits under their clothes and are able to get some swimming in with a nearly empty pool and hot tub.
They are also usually anxious to hit up the pizza place and eventually one of them will join us back at the table for a slice.
You can't get into your cabin until 1:00pm, so it gives us plenty of time to just enjoy the ship (and hopefully good weather).
Once you get into your cabin you still have plenty of time before the Sail Away party. I usually start unpacking and the kids check into the teen/tween clubs. Courtney usually comes back and orders room service before the safety drill just 'cause she can. Usually a Mickey bar or a piece of cake.
Everyone does the safety drill and then heads to Deck 9 for the party. I, personally, like to stake out a spot on Deck 10 for a better view. Although the kids will run back and forth between the dance floor on Deck 9 and Deck 10 up where I'm at.
So, that's my plan. Other people have different preferences. But this works out great for our family. If you're eating on Deck 9 too I'll save you a place at our table!