1. Leave fear of new ideas -- the cause of most knee-jerk reactions -- out of any formulation of premises and conclusions; do not foam at the mouth.
2. Express hope that the person whose ideas you're critiquing will come around to seeing things your way.
3. Express awareness of the possibility that you are in error, and that the person whose ideas you're critiquing may be able to provide you with a learning experience.
Failing to adhere to even one of these three will eventually lead to your species fighting wars with itself.