First thing - don't eat lunch before boarding the ship - there is a terrific embarkation day buffet.
Second, don't miss ANY dinners - they are terrific. When we cruise, after the second night on board we start skipping lunch. We all enjoy breakfast and as I said, dinners are not to be missed, but there gets to be a point where you can't continue eating (and I'm NOT a small guy!!) and something has to give and it's lunch - DW and the kids gennerally skip it to - ok teenage boys will never stop - but he slows down!
Third, get to the port before noon so you can get checked in and on board. THis will give you plenty of time to participate in the "ressie rush" if needed, sign any children in the club/lab and gives you a chance to visit the teen club and councilors (before it becomes off limits to parents). Then you will have plenty of time to explore the ship before and after the safety drill. The safety drill will confuse you a litte because they open up stairways and doors that are normally off limits to guests - and you will not be able to use them the rest of the cruise. I remember thinking - "Hey, there used to be a stairway around here somewhere" After multiple cruises, I finally figured out what was going on.