Research and anticipate your opponent's main points and arguments. Write down any other positions that may be offered against your argument.
Begin writing. Make your claim, and present your thesis. What is it that you are arguing, and why? Make your opening interesting, catching the audience's attention.
Include the data to support your claim. When presenting your data, create a "warranty," stating why and how your data supports your claim. Present any evidence to support the warranty. This ensures your argument has several layers of defense.
State the claims of your opposition and their supporting data. Address any further objections or counterarguments that may arise against your proposal.
After each objection or argument against your proposal, write your own argument against that objection, using data to support your claim.
Form your conclusion, making sure to reiterate your thesis, while summarizing the evidence presented during your speech.