More than half of those who've never taken a cruise would like to do so, according to a 2006 survey by the Cruise Lines International Association.

But if you've never cruised before, the concept might sound intimidating. How do you book? How do you dress for dinner? How much do you tip?

Here are answers to common questions of first-time cruisers:

-- Must I use a travel agent to book a cruise?

Every cruise line has a Web site. You can easily book your own trip.

But which cruise is right for you? Do you like partying in discos and bars, or would you prefer Tommy Dorsey-style music in the cocktail lounge? For shore excursions, are you up for kayaking, or do you want the trolley tour? Do your kids need a baby-sitter or a teen lounge?

You can compare what each ship offers, or get advice from Web sites such as CruiseCritic.com or TripAdvisor.com.

But it costs nothing extra to consult a travel agent, "and you've got a professional who may actually have seen or been on the ship doing the work for you," said CLIA spokesman Bob Sharak.

Do I have to eat in the formal dining room with strangers and dress for dinner?

Most ships have various dining options: buffets, cafes, specialty restaurants and formal dining rooms. Many ships offer "dress casual" nights in the formal dining rooms. But even formal dress nights don't necessarily mean tuxedos and gowns; a suit or dress will do.

Some cruise lines let you sit where you want in the dining room. If not, chances are you'll have fun meeting other people at your table.

-- What should I pack?

Bring flip-flops or other slip-on shoes, and a robe or cover-up for walking from the pool to your cabin.

Pack for the weather. A New England fall foliage cruise might mean a few cold days at sea. Alaska in August? Bring rain gear.

Some ships have self-serve washing machines and dryers, some don't. Sending dirty clothes out to the ship's laundry can be costly. So bring enough clothing for your trip, or find a coin-op laundry in port. Your state room bathroom may have a pullout clothesline for drying swimsuits or hand-washed items.

-- Does the price include everything?

Cruise prices include the room, food and some beverages. Free drinks might include coffee, tea, iced tea, lemonade and, with breakfast, juice.

Luxury cruise lines don't charge extra for wine or liquor. On many other lines, you can't even get soda for free, but you can buy beverage packages ($6 a day is typical).

You could spend a lot on alcohol, casinos, spas, Internet access and video games.

If you're on a budget, stick to free activities - pool, gym, shows and, in port, a stroll through town or the beach instead of a helicopter tour.

If you want shore excursions, you'll find vendors offering tours in each port. They may charge less than the cruise line charges for similar outings.

But if you have your heart set on a certain activity, book in advance through the cruise line and consider it money well-spent. Popular tours will sell out.

"If you're dying to do a glacier sightseeing trip in Alaska, you've booked it in advance and it's taken care of," said Sharak. "Or if your tour bus gets a flat tire and is tardy coming back to the ship, if you've booked it through the cruise line, that ship is not going to leave without you."

-- How much and whom do I tip?

Some luxury lines forbid tipping. Other lines recommend certain amounts. Some offer prepaid gratuity options or levy a service charge for dining room staff and the person who cleans your room. A typical tip for stateroom attendants is $3.50 a day; dining room staff tips run $5-$10 per day, divided among your waiter, wine steward and maitre d'.

With prepayments, you're charged a gratuity for each person in your party for each day. So even if your kids never eat in the dining room, prepaid tips will go to servers on their behalf. You might be better off deciding on tips near the end of your cruise, in case it makes more sense to tip a buffet worker who delighted your children each night with a magic trick.