weather conditions- if performing outside coverage for electric equipment in case of rain is needed. shelter for audience and stage should also be thought about.
trip hazard- cable organisers would be great in order to avoid a trip or a fall on or off stage. cable ties would also be a good option as it would be easier to put the cables out of sight to avoid any accidents and without it looking messy.
ear plugs- noises above 85db are harmful so ear plugs are necessary at practices and gigs. At concerts the noise levels are roughly 120-129db which will effect the hearing of the audience.
footwear- running/jumping/walking on stage could be dangerous especially if the stage is high or wet from weather conditions. Footwear that’s comfortable with good grip should prevent any sort of accident on stage.
first aid- accidents do happen so making sure that a first aid kit is somewhere nearby or near the stage would be really could. if outside as a festival an ambulance could be used in case of any more serious accidents.
safety and emergency exits- in case of fire emergency exits to be visible for everyone. and fire extinguishers on site.