Sincerity
Sincere convictions earnestly expressed. You can't convince others of what you don't believe.

Knowledge
Unquestioned knowledge of your subject. You cannot explain to others what you do not understand.

Preparation
You are indebted to the audience for the privilege they have given you. A good speech is the best expression of your gratitude. Is a speech worth giving if it is not prepared to perfection?

 Practice
Practice at home - not before an audience.