If you've never been on a cruise before and want to just try one out, go for one of the 3 or 4 day ones if they have those type leaving from a port that's convenient for you. If you want to jump right in and go for 7 days, the ones down the Pacific coast of Mexico are fairly reasonable. If you can afford it, a room with a balcony is the only way to go. And go into it knowing that the standard claim of the fare being all inclusive isn't true. Alcohol is of course extra and while you can try to sneak your own supply on board, you'll also need to sneak your mixers on since most lines charge extra for soft drinks. You can plan on spending way more than just the basic cost of the cruise for sure. Everybody will have their hand out, even the (usually smarmy) dining room captain who simply glides past your table with a quick greeting and then expects a major gratuity in his envelope at the end of the cruise.
If you don't want to be part of a cattle call, there are some cruise lines that provide "freestyle" programs that don't require you to eat at the same time at the same table with the same people every night. All cruises offer alternatives to the formal dining experience if you want to skip it for an evening. And speaking of formal, they all have at least one formal night, a really stupid kind of thing but people seem to like it, pretending like they're Fred and Ginger type sophisticates or whatever. This doesn't work for guys like me and my partner who prefer to wear as little as possible as often as possible.
Carnival is the lowest common denominator and appeals to that same demographic. They run their ships so hard for so long, the dining room (at the back end where the engine room is) vibrated so badly the glasses on our tables shook. I'd not cruise with them again. Constantly being barked at over the PA regarding the next item on the activity director's agenda--they even break into the TV show you might be watching in your room with the same announcements. My partner and I went down to the dining room the first night wearing slacks and saw so many men in shorts that it was clear they weren't enforcing their own dress code and we wore shorts to dinner the rest of the time. If you're looking for a more refined cruising experience, you don't want to be on a Carnival ship. We only ended up on Carnival because we were part of a group whose obviously easily impressed organizers chose that line. Our experience on a prior cruise with Royal Caribbean was much nicer.
I've heard that Celebrity is not only expensive but also tends to have a predominantly geriatric crowd. Best way to approach it is do your research, plan way ahead, and book way ahead to get the best room possible. The earlier you book, the more likely that you will be upgraded for free to a more expensive and desirable cabin.
NOT. that said Many people truly enjoy it.
