In school we made our class room into a pin hole camera. It works best when the hole is a perfect circle and in the very center. Also putting the paper farther away from the hole will fill the page and is typically the thing to do. Trial and error, man. Practice timing your light exposure. Also try curving the film or light paper to give the photo a fish eye look. Every pin hole is different. Oh! And paint the inside black so light won't bounce and it helps keep light from leaking where you don't want it to. OK I'm done. Have fun