I used a small paring knife to do most of the cuts. To make dots, I stuck the potato with a chopstick point.
I used acrylic paint for the stamping because it is water based. Since this paint is quite thick, my first prints weren't very crisp. I didn't want to thin in with water for fear of losing its opaquness. I discovered that applying the paint to the potato stamp via a sponge made for a more consistent print.
I printed on a large sheet of craft paper. It should make for great giftwrap.