The most important thing to consider when buying a cruise is to understand the kind of cruise experience offered by a particular cruise line and a particular ship. Being a well-informed purchaser is essential. If you want quiet elegance, then the informal and sometimes rowdy atmosphere of a party ship may make you wish you had asked a few more questions of your travel agent. A good agent will make sure you understand the atmosphere on-board a particular ship before you buy. If you want to avoid formal dining, make sure you check to see if this is required on the ship you're interested in.
Entertainment also varies considerably in terms of type and quality.
Knowing what you want and taking the time to make sure that a particular line and ship match your expectations will make all the difference. References Two excellent references will help you to narrow the field before talking to an agent. This guide contains ratings in 20 categories for most of the world's cruise ships. It is broken down by ship with cross-referenced tables making it easy to find information. The second reference to consider is Frommer's Cruises which comes out every two years and is organized by cruise lines rather than by ship.