Be aware, you might not be a fan of early booking, but there is no other way if you want to see certain destinations.
Travelers can be divided into few categories: those who plan ahead their vacation and those who prefer to book the last minute deals and always have their suitcases on the go. However when it comes to choosing a cruise, there are few tricks your should be aware of. Some of the destinations and times, like holiday seasons are not available for fast booking and the only way to catch such a cruise is by booking it in advance, like a year. No jokes here:
Holiday cruises
Cruises on new ships
Popular cruise ships
Short season itineraries
Expedition cruises
For the most part I agree with these suggestions that booking early for some cruises is a requirement. A lot depends upon how flexible you are on dates and stateroom category.
I have cruised a few times for New Years Eve and did not find it that difficult to find a suitable cruise 2-3 months out. I have also sailed on many of the popular cruise ships including Royal Caribbean's Oasis of the Seas and Allure of the Seas ,booking them 3-4 months from the sailing. When we did our Alaska cruise we did book 8 months out and although we wanted a balcony room, none were available even then. Many cruise ships to Alaska are smaller ships that do not have as many balcony rooms. Next time we go to Alaska (yes it is worth doing more than once) I will book at least one year in advance.