Origami Basics – Valley Fold
For the Valley Fold, start with a square paper, with the white side facing up.
Fold one of the vertical edges towards the other vertical edge. For this fold, we will not be aligning the two edges, but instead fold a little before the edge. This will end in a paper that is a little wide on one side of the crease and smaller on the other.
Note: To get a perfectly straight crease, align the two horizontal edges at the top and bottom.If they align correctly, the crease will also be straight.
Once the edges are aligned, crease well so that you end up with a single, sharp valley fold