The only thing you need is paper, although I used a vintage greeting card and it worked perfectly. Here's how you do it.
•If your paper is not already a square, cut it so that it is. The size of the square doesn't matter- just keep in mind that the finished bookmark will be 1/4 the size of the paper so don't go too small.
•Fold the paper in half. Open it and fold in half again the other way, forming a cross.
•Make one diagonal fold. Crease this fold forward and backward.
•Your project should now contain 4 squares, 2 with creases through the center and 2 without. Choose one of the squares with no crease and fold it so that the corner of the paper meets the center point.
•In the same direction as the last fold, fold the paper upward so that you have a triangle shape.
•Pick up the paper. The left and right sides of your triangle should each have creases. Use these creases to fold the corners in toward the center.
•Continue folding the corners inward until they meet in the middle. Your bookmark should be starting to take shape.
•Press the finished bookmark flat on the front and back. All done!
•I made about a half dozen of them so I can use them to mark all my favorite passages while I read.