I actually don't know what a podcast is, but since it involves us recording our speech, I'll do the best i can to outline my guiding principles....
1. Fluency - clarity and accuracy, but how natural you say it is key!
2. Creativity - using our (limited) knowledge of Japanese in creative and new ways.
3. Team participation - it cannot be one person talking all the time, but rather an even share
4. Effort - how much effort you put into the project...
Hope that helps~!