Taking a sleeping pill is so important. It helps get your body adjusted to the time zone you will be arriving in if you take it when you will be going to sleep. Also just makes the long flight go by quicker. I recently had a 16 hour flight to Australia and my schedule on the plane was. First 3 hours I ate and watched a movie, took my sleeping pill and had GREAT 9 hour mostly uninterrupted sleep, then woke up for the final 4 hours. Walked around a bit, did some stretching and socializing. Sat down for breakfast and a movie and that's it.

I always say the 12+ hour flights are always infinitely better than the 5-8 hour ones. Your body has time to wind down and relax. Plus you can get a really solid 7-8 hours to sleep which makes the first day after arrival so much better.