There's not much you can do depending on the in flight malfunction. Hit RTH if you feel you've lost control and hopefully it does its job, which provided it's airworthy, has a GPS lock, and the RTH altitude is set high enough it WILL come back. If there's a major malfunction in the air it's probably going to hit the ground pretty hard, and you'll just have to find it and pick up the pieces.
In a loss of GPS the aircraft reverts to ATTI (attitude) mode which means it drifts in the wind and takes a more measured hand and cool head to control. You can practice in ATTI by moving the selector switch to A instead of S or P modes.
You can get a tracker to attach to the drone in case you lose it. Some are RFID and some are cellular / bluetooth.
Post crash procedure is to pick up the pieces / boot the aircraft and take stock of what works and what doesn't. If you feel the crash was not caused by your own hand, you contact DJI. Some have had good service (ME) and others have had horror stories of experience with DJI customer service.
Malfunction on the ground procedure is to pack it back up and take it inside and contact DJI - See above.
