On the QE2 you should dress in the suggested manner for each night. If it's a formal night you will find that most people dress up; not all in long dresses, but certainly something special; informal nights - a dress or black trousers and a nice top are OK. A LBD with some sparkly jewellery will do the trick. Through the day you can wear whatever you are comfortable in. Check the FAQ on their website.
You will find your dress code each day in your daily programme.Itend to take black evening trousers and a skirt,with several diffrent tops to mix and match.Day times a nice skirt or slacks is quite ok.