Events and particularly music events require much planning and thought beforehand. In most cases, it is recommended that a team is put in place to take control of this planning process. The risks must be considered, and solutions put in place.
There are a series of different risks involved when preparing for a music event, from the risk of infection to the risk of injury caused by poor planning, especially near points of egress. 
Paying extra attention to laws and legislation can ensure you are providing a safe environment for both workers and audiences alike. This includes The Health and Safety at Work Act 1974 and The Noise at Work Regulations 2005.