A debate competition.

Well,this Friday i and my friends-Lee and Chung will compete with my others friends which are Weddy,Madeline and Macpherson in debate. I and my team member support the title "Internet Bring Beneficial" while my other three friends against the title. I am third speaker but i think i would not do well. Because i always don't have confident to talk in front of my friends and teacher. I'm also very nervous. Can anyone tell me ways to stay calm and talk confidently? I really need help on this. My friend,Lee is sick today. So our group will compete this Friday. So i am relief when i know this time i can prepare. If anyone can help me,please give any advice. Thanks. Have a nice day!