0KedaDibandion 9 years ago ReplyUpvoteI've done this using a dull knife (like a pad knife or a non-serrated butter knife) and a ruler. Basically you want to cut the paper, but only enough to fold it, not enough to actually cut it. I also have had luck with a dull knife and a countertop separation when I can't find a ruler. My counter is made of two pieces and there is an indentation where the two pieces meet. I line up the cardstock on that line, and then use the knife to indent the paper into the indentation.