Well the key with CX F is to sleep around to maximise your awake time to enjoy the experience. For this CX883 is not the most ideal flight - on the west coast transpacs I prefer CX885/CX879 as this means after a full night's sleep in a hotel I get to stay awake for all if not most of the flight, and then crash once I reach HK.
However when availibility or schedule has forced me to take the overnighters I like to do the following:
1) Take an afternoon or evening nap that day
2) Enjoy relaxed supper on board and watch a few movies. Probably stay up for the first 7hours of the flight, help myself to the snack menu before taking a nap. Get around 5 hours of sleep and then enough time to enjoy breakfast freshen up and land - not too jetlagged on arrival that way.


Either way - enjoy the experience like most others have said - have no expectations, make conversations with the crew - they always respond to friendly / less uptight customers with a lot of warmth and are willing to go out of their way for you if you are friendly.
I often do little things to ease their burden - for example if I am in doubt between two main courses I ask them how their catering load is and suggest that I'd be ok with either a or b, if they are running low. 99% of the time I still get my first choice and they are so touched with the gesture that they really go out of their way for me.

Enjoy CX F - you'll be quite spoiled after that...