I brought my 11 month old son to New Zealand, I bought a child's seat for him, because he was already quite big and heavy. If your baby is around 6 months, you can order a bassinet.
For night flight, my son slept most of the time. During the day flight, frequent snacks, all sorts of toys, visits to toilet, walks to and fro the aisle, naps.
I bought a portable VCD player for my 3.5 yo son, he watched 4 VCDs and took a nap, many drinks and snack during the 12 hours flight.
Better get more adults to go together, otherwise you are so busy taking care of the child, no spare hand to take pictures, and no mood to enjoy the trip.
(I brought my maid along, she took care of the luggages, I took care of my younger son, and my hubby took care of my elder one. when my elder one vomited in the bus, my hubby was so upset that he refused to take pictures! So we don't have any pictures for that part of journey. :-( )
I have to add this: My elder son was so sweet, he tried to comfort my hubby by saying, "Baba, I feel much better after I have taken the corns"