When arriving at the scene of an accident it is important to firstly ensure the safety of the casualty, bystanders and the first aiders themselves. The scene survey can be conducted by remembering the Acronym CLAP.
Stop at the scene, don't panic and take a deep breath. Act quickly to ensure the safety of all and prioritise the risk of vehicular traffic.
Scan the area for anything that could cause harm to you, the casualty or bystanders. Identifying known hazards at this point could prevent further casualties. Examples include the risk of electricity and fast moving water.
Gather information from both the casualty and / or bystanders at the scene. Use the principles of History, Signs and Symptoms to identify what is going on.
Protect yourself and the casualty from cross infection by wearing gloves and using sterile equipment from a first aid kit. Ensure casualty's are prioritized using the principles of Breathing, Bleeding, Fractures / Bones and other injuries.
Gain as much assistance as possible from bystanders and get the required information to the emergency services. The emergency services won't come unless you call them and they will not prioritize you unless the required information is given. It is possible to speed this process up (potentially saving the casualty) by being clear, concise and to straight to the point.