Slightly (or worse) sleep-deprived when boarding (easy, very sleep-deprived is my normal state anyways), NC headphones (always in briefcase), lots of water/diet-coke (and a chat with the FAs to have them not wake you for breakfast) and a melatonine tends to get me zzzZZZz for about 6-8h -- assuming that the seat is acceptable (long-haul C or better). Taking the melatonine at the right time of the flight, and I wake up ready for my destination as fresh as if I'd spent the nights in the presidential suite at the nearest InterContinental for the last month.....ok, maybe not, but I *am* rather easy when it comes to sleep and to fighting jet-lag. (handy for a FTer...)

I tend to not drink much alcohol in general, and less on flights since it makes my sleep irregular and restless, and due to the dry air + alcohol, I wake up with a headache. If the FAs have a bottle of something that intrigues me I may have a single glass, but I'm over the time in my youth when I'd drink my way through 6 mini-bottles of questionable champaign on a 2h intra-European flight in C (of course, most airline companies are also over the time where they'd give out that much free booze, even in C....)