Seems like most of the obvious tips have been given. Drink lots of water and bring plenty of snacks. Bring a book or a phone/iPad + chargers. WiFi speeds are great but download a few movies/TV episodes/podcasts just to be safe. Bring an extra set of headphones too (AirPod Pro and Bose QCs are the best in their categories). I do 12 hours on a 737 with a short break all the time when doing mileage runs and don't really think anything of it anymore. Being in F obviously helps. If you are in Y, pray for an empty middle.