4. Respect the dress code
Some cruise lines have very strict rules around dress code, for example, if you go on a Cunard cruise they have very strict formal nights or gala nights where gentleman have to wear a black suit and tie or a tuxedo and ladies wear equivalent like glamorous gowns or cocktail gowns.
Even on their less formal nights, the gentlemen are required to wear a jacket with no tie. They have a strict rule.