Make sure to have walking shoes on at all times and have tip money in your pocket. From picking your luggage up at the airport to getting onto the ship, it is a lot of walking. If you get a porter at the airport, he will take you directly to the NCL area where you will sign in for your ship transfer, and use a Porter on disembarkation day. Porters know how to move you around very, very, quickly, whether you have a shore excursion or transportation to the airport.
If you are only booking a few shore excursions, do so at a port where the ship is tendering. This will prevent you from having to book a tender ahead of time. Shore excursions at these ports are prearranged for you, so all you have to do is show up at your designated meeting place, which is usually the Epic Theater. From that point they handle everything else that will get you to your excursion point.
If you have to take an elevator and cannot walk the stairs, make sure to give yourself plenty of time to get to your destination. Elevators are always slow and often stop on your floor already full!