There are many security providers and it is hard to figure out which one to choose the differences between all of them. Fire safety, safety, rescue / medical and hygiene, it is there for important to make you have.
But once the selection is made, the hard part still lies ahead. You need to establish communication, organise action points and make sure every part of the contract is respected, otherwise you do not control the security of your event anymore. The management of your providers is ofen the key point in the success of your mission.