Our box will include a wooden framing with a styrofoam layer on the inside to insulate everything. It will be made mainly with duct tape to make sure that there are minimal cracks.
My team's box didn't win because of some flaws that we either forgot to add or didn't have enough time to implement. But it did come in about 3rd place!
I learned that in making an insulated anything you need to always insulate everything you can think of. Ours wasn't insulated at the top and bottom of our box so heat could enter that way.