Congratulations on picking Sun Princess for your first cruise. I am an original crewmember on the Sun. She is a beautiful vessel. Consider formal nights FORMAL. Go all out. For men, bring your tux or rent one. There is a website called cruiselineformal.com (or something similar) that will deliver your tux to your cabin. It will be there when you get on board. You leave it in the cabin when you leave. Simple as that. Ladies: it's your night to shine. Pull out all the stops. Dont go semi formal on a formal night. Even if you normally dont dress in formalware, just do it. There are normally 2 formal nights per cruise.