Never respond to an angry person with a fiery comeback, even if he deserves it...Don't allow his anger to become your anger.
Focus on making yourself better, not on thinking that you are better.
Don't feel the need to vent or complain, no matter how badly you would like to express your feelings. When it comes to speaking of those in power, always think of the consequences. Think about how those around you will perceive what you have to say. Will what you say be of advantage to you or will it hurt you in the end?