Write an article based on this "Fold an 8.5 by 11 inch (22 by 28 cm) piece paper in half lengthwise and then unfold it."
Either fold the right side of the paper to the left, or the left side of the paper to the right. Make sure the edges of the paper match up so that you create a neat vertical crease down its center. Unfold the paper once you've made a defined crease.  Pinch the crease with your thumb and index fingers and run them along it to make it more firm. To make the crease even firmer, you can unfold the 2 halves, turn the paper over, and fold them again. This will create a defined crease along both sides of the paper.