Modern preventative medications are also readily available. All these factors work together to lessen your chance of seasickness. You can book your cruise in calm waters aboard a larger modern ship with stabilizers. Book a mid-ship, lower level inside cabin, those have the most stable ride. Speak with your doctor before you leave for recommendations of preventative medications you could use.
Some people find an accupressure bracelet around the wrists to be helpful.
Once on board, spend some time on deck and focus on a fixed point of the horizon. This helps your body to adjust to the motion. Avoid alcohol, it will only increase the symptoms of motion sickness. You should check, but your ship will probably have an infirmary with a doctor and nurse on staff and available 24 hours. If you have any pre-existing conditions that might need medical attention while on board, notify the Cruise Line in advance of booking to see if the type of assistance you ll need is available.