Airspeed is life to your model, altitude is life insurance. No airplane ever collided with the sky. Always fly your airplane with your head, not just your hands. Never let your model go somewhere your brain didn't get to five seconds earlier. The probability of model survival is equal to the angle of arrival.
Good judgement comes from experience and experience comes from bad judgement.
There are three simple rules for making a smooth landing. Unfortunately, no one knows what they are. It's a good landing if you can still bend the landing gear back to its normal position. A fool and his money are soon flying a more acrobatic model than he can handle. The nicer an airplane looks, the more likely it is to crash.