NUMBER 1 RULE - STAY ONLY IN THE PUBLIC AREAS (this means, nobody else's room, no employee only areas, etc)
Also, we always eat our meals together - breakfast is easy because we get the kids up when we get up (they hate it, but you don't want them wasting their cruise by sleeping the whole time). Then we usually meet at a specific time on the Lido deck for lunch, and we always eat in the dining room for dinner. I figure, it is still a family vacation, and although they have their freedom during the day and in the evenings, they still have to eat with us.
My biggest problem is getting them to turn in at night, but we have never had a problem with finding them if we need to - there are only so many places on the ship and they usually are in the same few places, so we know where to look first.