The major difference was gluing the printed pieces to black cardstock. This seemed to help block out a lot more light. I also spent a bit more time getting the pinhole itself more accurate. The resulting photographs are not ground shattering, but at least the camera worked this time!
It was fun trying photography without a lens. Very much a back to basics experience especially compared to modern digital technology. Not only did I forget what it is like not having an instant preview, but not hearing a shutter click was very odd.
Click a picture to see a larger view.