I have cruised with Princess twice (both on the Regal) and have two more cruises booked (one on the Sky and the other on the Royal). These are all medallion class ships so these tips are specific to Princess medallion class. I am going to cover the cruise itself and not booking and cabin choice.
Here are A few tips for those who haven't cruised on medallion class or Princess before. I have been on Princess twice and have two more cruises booked. I have been on other cruise lines (Carnival and Norwegian) but find Princess to my cup of (afternoon) tea! So if you've never been on Princess before, here are some tips to get the most out of your Princess voyage.
Princess does a lot things other cruise lines do, they just seem to do them better, they also have have unique features you won't find on other cruise lines (yet). One of the unique features is the medallion! On medallion class ships the card key has been replaced by a medallion (which uses Near Field Communication (NFC) and Bluetooth connectivity). The medallions are what you use onboard ship to enter your room or purchase anything, they can also be used in conjuction with the medallion app to message others, find others , find your way around the ship, order drinks or order room service. Here is the link to medallion class info https://www.princess.com/ships-and-experience/ocean-medallion/.
The medallion app can be used to order drinks and the wait staff will find you! The first drink ordered through the medallion app is free (at some point Princess will probably stop this but it was true at the time of writing), its a really nice way to start your cruise by the pool after lunch and before the muster. On the first or second day onboard you will get invited to the captains circle meeting, its 20 minutes and you will be rewarded with a free drink coupon for your time. Keeping with the booze theme, Princess allows you to bring a bottle of wine per adult onboard, which is only subject to a corkage fee if you drink it in the dining room, so if you like a glass of wine on your balcony and want to save some money, take advantage of that (don't forget a corkscrew and stopper).
Another Princess favorite of mine are the afternoon teas. On sea days at 3pm there is an afternoon tea with sandwiches, cakes and the English favorite of scones with clotted cream and jam. In keeping with the British theme, there is, usually, also a Pub lunch on one sea days! Enjoy such British favorites as Fish and chips (with mushy peas), Chicken curry, Scampi, bread and butter pudding and Trifle!
The international cafe is Princesses best kept secret, it is open 24 hours and has wonderful snacks, sandwiches, pies and pastries. It has donuts every morning to die for!
Another favorite is the movies under the Stars, not secret, in fact its one thing you can't miss, a huge screen overlooking the pool! During the day they play concerts and will show special events (NFL games for instance) but in the evening they play, just out of the cinema, movies.