I have been cruising for several years, but this is the first one on Princess. I will try and give you a personal review of what I encountered. So let's go.
BEFORE YOU LEAVE -- Before you leave there are some things that you will need. First you must have a current passport. After December, 2005, you must have a current passport to travel. So get this first. Next, the Diamond Princess (DP for short) has only limited outlets in the room. Think about bringing an electrical strip with 4-5 outlets. This will help you if you have several things that need charging.
THE SHIP -- The ship is large, but getting around is very simple. You will be provided a map of the ship when you get to your stateroom. Really, the only thing that you need to remember is if you want to eat deck 14, if you want to see the ship start on deck 6 and go to the middle. All of the areas are either a deck above you or below you. Not being on a Princess line before, I was not really sure what to expect. I was disappointed when we arrived and found out the average age group was in the senior age. My wife and I are in the 50's and there was nothing for our age group. Most of the entertainment was geared around the seniors. The highlight was needle point and how to make your needle point impressive. Bingo was another highlight, won $200.00 and thought I was going to get mugged. The point is, when making your reservation, find out from other people what age group are expected, you may want to change to another line. The ship is very clean. This is where DP excels, most cruise line clean during the day. You have to move out of the way so that they can clean. DP cleans at night when most people are asleep. Good job.