I will be a member of the jury for a debate on Monday. There are several things that I expect to see from both teams.

The arguments of both teams need to be well prepared. I want all of the arguments to be thorough and well organized. If the argument is confusing for me to understand, I will be less likely to pick it. I also do not want teams to state the obvious, I want to delve into their topic, and say something that I have not heard before. I want to be compelled by both arguments.
The more unique and interesting a point in the argument is, the more likely I will be to pick it. In my opinion, there is nothing worse than an information that you already know in an argument because it makes the argument boring.

I want teams to have strong counterarguments, and to do this the team must think about what the other team will potentially say. I expect teams to be prepared for counter arguments. To be well-prepared teams must do thorough research for and against their side. Even though the teams need to be well prepared, they need to listen to what the other team says to be able to give a good rebuttal.