Travelling is great… 15-hour flights are not.
Check in online.
Most airlines offer check in 24 hours before your flight departs. Not only can you choose your seat, but sometimes the earlier you check in, the higher your chances are of being upgraded.
When choosing your seat, avoid the first few rows of each seating section.
That's usually where families with kids are seated, so there's a higher chance of a (possibly screaming) baby being near you.
Try to get a seat near the wing.
During turbulence, the plane rocks like a see-saw. If you're in the middle, it'll feel a little less bumpy.