Origami is customarily done with square sheets of paper. Lined notebook paper is usually rectangular and does not lend itself naturally to origami patterns. However, there is a simple way to square a sheet of lined paper without using a ruler or other measuring device. A couple of folds and a cut will give you a square paper that you can use to make origami figures.
Place the lined notebook paper on the table in front of you.
Bring either one of the lower corners up to the opposite edge of the paper. Make sure the bottom edge of the paper lines up exactly with the side of the sheet of lined paper.
Crease the paper along the diagonal fold formed. There will be a rectangular, horizontal strip of the lined paper protruding past the folded triangular flap at the top.
Fold the rectangular strip down along the line formed by the triangular flap. Crease the fold. Unfold the strip and the triangular flap. Now you will see, in addition to a diagonal crease, a horizontal crease across the top.
Cut the paper along the horizontal crease with scissors. For a cleaner cut, you can place a ruler along the horizontal crease, hold it in place, and cut the rectangular strip with a sharp craft knife.
Discard the rectangular strip of paper and use the square sheet of paper for your origami project.
You can draw or color on the lined notebook paper after making it into a square shape to add interest to your finished origami object.
This method works with any rectangular sheet of paper, including printer paper and decorative gift wrap.
You can perform the same procedure on the rectangular strip, making smaller squares instead of discarding it. Smaller squares of paper require more skill to turn into finished origami models, however.