I've flown LAX/SFO to SYD in F quite a few times in the last several years. My top three:

1. The timing (time of day) of the LAX-SYD flight is great -- don't eat too much before hand so you can really enjoy the meal. Take your time, have wine and some drinks. The timing is such that you are getting on at night, and getting off the plane 'in the morning' albeit 14 hours later. For me this equates to 3-4 hours of meal and movie time, then a solid 9 hours of sleep. I usually skipped the breakfast onboard. The return flight is even better, afternoon departure and sleep the night, then get up in time to land in the morning.

2. The suites are great in the 'bed' position, but don't forget that the entire side armrest (aisle side) drops down -- this makes you feel much less constrained and makes sleeping easy.

3. Maybe not pajamas, but do wear something really really comfortable. I used to change into shorts since I tend to get warm on planes (and they sometimes jack up the heat to put people to sleep after mealtime).

4. Bonus tip: with your F ticket, go to the NZ and SQ lounges in SYD on your return. They are quite nice and have some great food. The NZ and SQ people may tell you that you can go to the UA IFL, but just say you want to 'try them out'. Having said that, go to the UA IFL to see "A" the non-matron who is incredibly helpful and who has been there since the PanAm days.

Another bonus: If you can change to come back through SFO, and you have a long-enough layover (1.5 hours or more) you can use the SFO Arrivals lounge -- that shower feels really great after the long flight from SYD.

Congratulations and have a fantastic time.

-C