Even the most experienced pilots have a preflight checklist in the back of their heads. The reason for making and flying a craft like this is for fun or professional business. The last thing anyone wants is to be exposed to situations where things go crazy. So, let's gather some important notes about the things that should be checked before you fly:
The airframe/landing gear is not damaged
The props are secure, undamaged, and spin in the correct direction
The motors are secure and undamaged
The ESC is secure and undamaged
The GPS, telemetry, receiver, and transmitters cables are secured
The battery and other power connections and the voltage are correct
Notice that professional pilots who have bought a DJI Inspire quadcopter or any other expensive craft usually sit down and write a list, which they should always check before flying. It is a good idea to sit down and write a list according to your own quadcopter. The list depends on how many components and what stuff you have...