Notice the sample cabins shown in the brochure for the various categories. They are not about as big as a hotel room  :-).  They all have some sort of berths (twinsize can often be joined into queensize), dresser or desk, closet and bathroom, and provide you with air conditioning, a radio and/or TV and a phone.  Some have bathtubs, mini-fridges, more square feet or sitting areas, sitting rooms, verandahs (very desirable on Panama Canal and Alaska trips), portholes or windows.  Even the smallest cabins have been cleverly designed to appear more generous, and you may not really need that porthole if you're not in the cabin enough during the daytime to enjoy the view. Generally: 
 

• Outside cabins and those on higher decks cost more.
• Inside cabins can sometimes be identical to outside, except that there is a curtained wall in place of the window.
• Veranda cabins usually have sliding doors to a private balcony area.  Depending on the location, the veranda may be almost inadequate or absolutely huge.  These are most often desirable on itineraries like Alaska or Trans-canal where there is a beautiful view almost all day.  They can be almost useless on an ocean crossing, though.
• Wake veranda cabins on some ships the veranda can be double the normal size (or better).
  
• Forward cabins experience more motion and anchor noise.
• Aft cabins experience motion and engine noise. 
• Cabins at the forward corners are often shaped oddly.  You will either get a funny room or a little extra space.
• Night Owl cabins are very close to late-night noise
• If you're prone to motion sickness, stay amidships.
• Avoid cabins too near stairwells and elevators.
• Handicap-accessable cabins are more conveniently configured on the newer ships.
• Wheelchairs are available but not allowed off the ship in ports. 
• Service animals are infrequently allowed.  Get approval in writing at time of booking. 

The longer you wait to book your cruise, the more likely you will have to compromise location or category. 

The elusive inside cabin with a view

NCL's Norway... on Fjord deck there are insides that were once outsides that faced a New Orleans style patio that was recessed for wind protection. During France's conversion to Norway a pool was fitted into the patio "well." Now these outside turned inside cabins have picture windows complete with ironwork gratings facing into a catwalk illuminated by portholes into the pool. The outside doors to the cabins still exist (but aren't functional anymore).

Special Needs

Hearing-impaired individuals can also be accomodated with the latest in telecommunication equipment on some of the newer or retro-fitted ships.

Age Requirements

Sharing a cabin...how to help ensure a successful share 

1.  Communicate with the potential sharing partner, email is fine, but somewhere along the line, a phone call is in order.  Sometimes a subject not discussed will come up in a phone conversation that wouldn't happen in email. 

2.  Describe yourself fully to the potential sharer, and get a good description from them.  Some of the things that I look for are : 

Smoker?  --- For some people this is a killer.  But, even if the potential sharer is a smoker, you can agree to not smoke in the room/cabin.  If this won't work with you, then this is a show-stopper. 

Drinker? --- social or heavy?  -- This is important as some like to just get knee-walking, toilet-hugging drunk when vacationing.  If this is not for you, then don't share. 

Early riser?  Late Sleeper?  All-night partier?  -- this has to somewhat match your habits, but if the other agrees that when coming in late or arising early, that they will try to keep the noise down, it may still work. 

If you are sharing a cabin with another of the same sex, then you need some ground rules about bringing a 'guest' in the room for some action, straight or gay doesn't matter.  Its about privacy. 

If you are sharing a cabin with another of the same sex, you need to find out if they are straight or gay, and how that affects you.  Are you into the gay scene?  Are you tolerant of the gay scene?  If you can't answer yes to one or the other of those questions, it may make for a miserable share. Personally, I have shared with both straights and gays and no problems occured as we were just sharing a room and nothing else. 

If you are sharing with a member of the opposite sex, then things can be awkward for both.  Somewhere along the line you have to be upfront about what you expect.  I have shared with women before, that were not lovers or partners.  We kept sex out of the picture and it worked. 

You also should find out what each likes to do.  You may find a real friend on the cruise/vacation, or just a room/cabin mate. 

What about bad habits?  I snore like a trooper.  It is unfair to not let the potential sharer know that so they can decide.  They also need to be upfront about those things also. 

Ok, thats how I do it and it has worked for me.  I have never had an unsuccessful share to this point.  Of course, other than my Navy experience, I haven't made any cruises yet.