go faster!
if you make one small mistake, (the ice cream was the worst) you have to drop the entire tray, and begin again. these gets worse when you start to falter back and the person you are serving leaves and you are now stuck having to reset yourself for the next guest, by then you are stuck in this cycle of catch up. there is noting new in this game that has not been done many times before. try adding more room to grab stuff or someone to run the cash drawer.