I will be on her January 27th for the second time. I wouldn't call these "Secrets"? More like Tidbits I've gotten from Cruise Critic and from my own experience.
Bring a power strip as there is usually just two outlets, at least in my balcony cabin.
Margaritaville is a great alternative to the buffet for breakfast. It’s a smaller version of the buffet. Eggs, made to order omelets, sides, and such, just without all the lines from the buffet. Just walk in and seat yourself.
I've heard on the Sea Days there is a free lunch buffet at Moderno. One was Tastes of Spain and the other was Tastes of India. Very good Salad Bar.
On Sea Days Ocean Blue has a window from which you can purchase delicious Lobster Rolls.
If you plan on attending Cirque Dreams and Steam show pay a little extra for floor seating verses banquet seating.
If you want to SaiI with NCL again I would recommend getting their Credit Card and purchasing a couple Cruise Next Certificates. Both will provide you with onboard credit that will off set Norwegians "Feestyle" Cruising. I booked my balcony cabin more than 6 months out so was able to put down 2 Cruise Next certificates which was a $500 deposit.