Everyone has made the point so well I don't know why I'm typing except to echo their sentiments. I'll agree with a couple of folks who said find someone who is a cruise specialist. Those who deal with cruiselines, know the ships, cruise themselves, get regular client reviews of ships and peoples experiences, etc. have a good way of steering you the right direction. There is a big difference between many of the cruiselines. Even between ships and sailing dates. Length of cruise, children friendly, formal or informal, freestyle or fixed dining, avg passenger ages. All these things vary greatly. If you have an idea what the important criteria is to you a good agent can help match you to the right line, right ship, right budget.
Just being on Cruise-Chat give you a huge leg up on most cruisers to start with as far as a basis for finding the right cruise for themselves. This site is a great source of friendly, knowledgable and helpful information.
I've learned a lot from my fellow cruisers/chatters here. For that I thank you all.