Summarize the following:
Keep in mind that the cheaper your ticket is, the more add-on charges will be available on the ship, and the more expensive the ticket is up front, the more all-inclusive it is. Give yourself a set amount of money for spending so you can better plan which activities and options to participate in. Cruises can usually be booked up to 18 months in advance, guaranteeing your first choice of cruise and cabin location. Booking ahead of time will give you more options and availability, particularly if you're traveling with a large group. Some cruise lines offer incentives to book early, such as prepaid gratuities or a free dinner in a specialty restaurant, so planning ahead could save you some money. Generally, you can book a cruise as little as a week before embarking. Booking short notice gives you fewer options, but a better chance to get a good deal. Cruise lines also sometimes offer special short-notice deals and incentives for cruises that haven't filled completely. You'll find a variety of good deals and special offers during “Wave Season,” the name the cruise industry gives the time from January to March when most people buy their tickets.   You can often find good deals when booking directly through the cruise line. Travel agents often offer special perks and discounts like on-ship credit and prepaid gratuities. If you have time to research and compare prices and you know what you want, buying online directly through the cruise line can be a great way to find the best deals. However, experienced travel agents can also help you find the cruise line that best fits your preferences as well as the best rooms on the ship.  If you do choose to go with an agent, make sure they know what you want and your budget. Ask lots of questions and don’t let them push you into anything you aren’t completely happy with. Not all cabins are the same, so depending on your experience and budget, make sure to pick one that fits your needs.  If this is your first cruise, choose a midship cabin located on a lower deck. If you find out that you do tend to get seasick, this will be the best place for you as it experiences the least amount of movement. If you’re on a tighter budget, look into windowless rooms and “guarantees,” which may let you upgrade to a better room for free if one is available. If you have a bit more freedom with your budget, consider booking a balcony room with amazing views of the scenery as you cruise by. If it's your first cruise or the area is particularly hard to navigate, signing up for the cruise line-guided shore excursions is a great option. These excursions range from snorkeling and hiking to shopping at outdoor markets and wine-tasting. Consider what kind of excursion you're drawn to--active or sightseeing activities, full or half-day tours, guided or free time, and highlights or in-depth. While casual restaurants are mostly first come, first served, you should make reservations for any sit-down restaurants. Although many accept walk-ins, it is recommended that you book your visits ahead of time to guarantee your spot, particularly for the more popular restaurants.

Summary:
Set a budget. Book your ticket in advance for guaranteed availability. Book your ticket last-minute to catch a price break. Find a good deal. Book online or with an agent. Choose the best cabin to suit your needs. Book online excursions to match your interests. Find dining options ahead of time.