My goodness... to be honest, longhaul and shorthaul are like two totally different jobs sometimes!!!
First and foremost is the time away from home on Longhaul.
As for onboard you really need to keep those Juicerounds coming! LOL! But also regular security checks and cabin patrols even when all the pax are sleeping. The cabin service tends to take longer on longhaul and depending on how long the flight there could be multiple services every few hours.
You also have to be prepared for anything to happen at any time even when over vast expanses of water or desert where there maybe nowhere to land should the sh!t his the fan!!!