If you tend to get seasick, cabin location is really important. It is a question of engineering, really. The lower and more central you are in a ship, the less roll and sway you will feel. Even if you choose a balconied stateroom, choose the lowest level and the most midship one you can find. The higher decks and cabins at the very front (forward) or back (aft) of the ship will rock and roll the most.
When it comes to choosing suite accommodations, it is best to figure out how much space you really need, what amenities are important to you and what you can afford to spend. Suites on most ships are often the first category to sell out, partly because there are fewer of them, and partly because they often offer extremely good value. For this reason, it is important to decide early what kind of suite you would like.
On many ships, basic inside and outside cabins are usually the same size, the difference being that one has a porthole or picture window to let in natural light. Balcony cabins can also be the same size as standard insides and outsides, with the addition of the outdoor space on the verandah; sometimes the interior space is larger. A basic cabin, regardless of category, is referred to as a "standard" unless there is something about it that makes it different (such as physical layout, being handicapped accessible or a designated family cabin). With minisuites on up, you get bigger and bigger indoor and outdoor spaces.
Other pitfalls include service areas adjacent to or above your stateroom; show lounges or bars adjacent to, above or below your stateroom; and self-service launderettes across from your cabin. Other cabins that can be problematic are those that are situated low and at the back (because of their proximity to engine noise, vibration and anchor) or low and forward (because of bow thrusters).
best and worst cruise ship cabins
carnival cruise room layout
cruise ship cabins to avoid