Explain the argument that the opposing team is making. Start it out as "They say..." and then write a summary of the other team's main argument and opinion. An example would be, "They say capital punishment should be legal to punish those convicted of murder."
Write out why you disagree with the argument being made by the opposing team in the next section of your rebuttal. Using the example above, you might say something like, "While this would be true in a perfect system, there have been too many cases of a person being sentenced with capital punishment and put to death, who is later proven to be innocent."
Add a "Therefore" statement to you rebuttal. This statement summarizes your own argument for the topic. In the example, you would write, "Therefore, capital punishment should no longer be a legal form of punishment for those convicted of murder."
Read through your rebuttal to make sure your logic makes sense. Your reader or audience will need to be able to follow your train of thought as the rebuttal is read or presented. In the example above, the flow of logic works well, starting with the opponent's argument, stating the reason you are against the opponent's argument and then stating your own opinion on the topic.