I've been flying an F450 quad via FPV for about 4 years now. It endured many crashes (free-falls), some were caused by my actions, while some had to do with the work of electronics.

In this article I highlighted a few techniques/rules that will help you prevent serious damages:
Rule 1

Put all electronics (including the camera) inside the body. This will ensure they remain unscathed in case of a crash (arms and propellers will break, though).

Rule 2

Allow some extra length for wires running between the ESC and the motor. Wires often get torn off from the motor when the arms break. Do so and you won't have to buy a new motor or rewind it, if your quad crashes.

Duct taping the whole deal can be helpful, too (choose a color that matches the shade of the arm). Make sure the tape doesn't hold the wire too hard.

Rule 3

If, the ESCs are attached to the arms of your quad, shift them as close towards the base as possible. This will prevent damage of the ESC itself if the arm breaks (they tend to break at the point where the motor is attached).

Rule 4

Whenever possible, use ESCs that come without pre-installed connectors. If the quad crashes, the connectors will break off easily rendering the ESC useless.

Good luck and have fun!
This is the translated version. You can read the original Russian article here.