The biggest advice I could give you is to do plenty of shore excursions, but not the ones through the cruise line. Go onto tripadvisor.com and look into attractions in cities that will be your port of call. This is by far cheaper than what they offer through the cruise lines, and you will receive better service as well. A few years ago while on a cruise we stopped in Cancun but ahead of time booked an excursion through ed ventures. This company was highly rated on tripadvisor. When we meet the driver we found out we were the only ones so we had a private tour of the ruins while everyone else was crammed into a bus and payed almost twice as much!!!