Nobody enjoys flying and especially long haul economy class. It can be hell! With my work, I fly a lot, as I return home after each tour. So how do you make it easier? I ALWAYS volunteer for upgrades but NEVER get one.
I always ask if the flight is full. If it Is not full then I ask to be seated next to an empty seat. Worth a try and it does happen.
If you want a window seat then ask for one and if you want an aisle seat then ask.
Relax and try to keep occupied. Drink lots of water, but not too much alcohol. Free flowing drinks sounds good but to much alcohol at altitude is not good for you.