Lines such as Disney, Carnival, Princess, and Royal Caribbean will let you set up a "honeymoon registry" so that your wedding guests can help defray your celebratory cruise fare. For example, with Norwegian, if you are sailing on Norwegian Breakaway, your guests can treat you to onboard expenditures such as shore excursions, spa treatments, cocktails, a bottle of wine, and dinners at specialty restaurants including Le Bistro, Moderno Churrascaria, and La Cucina. With Disney, you can register for shore excursions, drink packages, and dinner for two at adults-only restaurants Palo and Remy.

Though you can book most gift- and party-related services and amenities online, many cruise lines have a dedicated support staff to help make arrangements for your cruise, like Princess's Celebrations Ambassadors. Contact cruise reps before your departure and they’ll make specific recommendations based on your needs, which may mean ordering Champagne and heart-shaped towel art for Valentine’s Day, or arranging tux rentals for an onboard wedding.

To help you create ready-made memories on board easily, most cruise lines have milestones covered with general or themed packages, as well as those geared toward children and teens. They usually include cabin decorations such as confetti, garlands, and balloons (plus a cake for birthdays), or Champagne, chocolates, and roses for honeymoons and anniversaries. Some include elaborate add-ons like spa treatments, dinner at specialty restaurants, bottles of wine, in-room breakfasts or canapés, and even invitations from the captain for private visits to the bridge. Wedding packages are in a completely different category, and typically incorporate a wedding cake, canapés, photography services, and an open bar for your party (see our guide to getting married at sea).

Most ships offer party food trays for gatherings of all sizes that include vegetables and dips, assorted pastries, canapés, cheeses, and fruit. Pair that with a wine package, and you’ll really have something to toast. Bonus: On some luxury lines, there may be no additional charge for the staff to arrange a small party in your suite.

Your iPhone camera is great, but cruise ships have professional photographers and videographers on premises to capture those times you'd rather focus on the experience in the moment. You can buy photo and video packages, but sometimes special or group events have different pricing.

If your celebration involves a big party, you can take advantage of a number of group benefits including fare discounts, free amenities, or assistance with trip planning. On Norwegian, if you book seven cabins (with 14 passengers), two of the passengers cruise for free. Or you can spread the wealth and let the person-of-honor cruise gratis, while the rest of the party each gets to choose a bonus freebie (such as an unlimited beverage package). On MSC Cruises, the group rate kicks in at eight staterooms, and the entire gang can use complimentary meeting spaces for themed cocktail parties, salsa dancing sessions, or cooking classes.