To start with, a debate is an argument in a formal manner on a certain topic on which different arguments are put forward and the debate is usually concluded by a vote on a certain argument.
Here are some tips that would help you to write a good debate :
Debates are usually held in teams so you should make sure in which position or sequence would you be speaking, or would you be opening the argument or not . In this way you can mentally prepare for your speech.
Research the topic very well. Jot down all the pros and cons of the topic and be specific about what you have to say.Do this as a part of team work.
Write an outline of the topic and point out the strongest aspects of each point.
Always address the judges fellow team mates and audience with a formal salutation like a Good Morning/Good Afternoon etc.
Introduce the topic clearly before proceeding.
Introduction to your argument should be such that it draws attention. It can be a quote or statistical data or any relevant event.
Back your argument with some strong points and be affirmative.
Work on developing a strong conclusion . Conclude back to the same theme from which you started.
Last but not the least, be confident and avoid stage fright.