My wife and I cruised from Barcelona to Venice on the Ruby Princess in May, 2011 and just loved it. Neither of us had ever been on a cruise before and did not think it would be something we would enjoy mainly because we had heard about all the food that is available 24 hour a day. We also imagined that your ship is sailing all the time and there would be nothing else to do. We were wrong! Another couple finally talked us into taking a cruise in September, 2010 with them but after flying to Venice and boarding the Ruby Princess, we had a death in the family and had to return home. We did not get to sail but we were glad we took out cruise insurance. We did arrive in Venice a day before checking in to board the ship and got to see St. Mark's Square, the Doge's Palace, St. Mark's Basilica, Bridge of Sighs and the Rialto Bridge. We stayed overnight at the Westin Europa & Regina Hotel in Venice which we fell in love with. It's only a quarter mile from St. Mark's Square and we enjoyed a great breakfast at their outside restaurant right on the Grand Canal.
We finally got to take our cruise this year but without our friends. We chose the "any time" dining and we met some wonder people each time we ate. Usually all the table were taken but if there were two seats open at a table, the other passengers were happy to let others join them. We met other passengers when we took the excursions and everyone was happy to exchange cameras so that couples could be in pictures together.
A few tips I would pass on to anyone taking a cruise are first to really consider taking out cruise insurance when you book your trip. It may cost a couple of hundred dollars more but it is worth it. Next, plan your itinerary so you know how much time you have in each port, what you most want to see in that time and read up on the different ports and attractions. I was able to find and tape shows on television about each port we were visiting by some travel advisers like Rick Steves, Rudy Maxa and Samantha Brown. Lastly, plan an extra day at the beginning and end of your trip. If flight delays occur, you will still be on time to the ship and catching your flight home after your cruise.