How do you make an accordion fold?

To make an accordion fold, you essentially create a series of alternating folds (mountain and valley folds). Here's how to do it:

1. Start with your paper. Place it on a flat surface.
2. Make the first fold. Fold the paper over onto itself, creating a crisp crease. This will be your first fold (either a "mountain" or a "valley" fold—the choice is yours to begin with).
3. Flip the paper over. If your first fold was a "mountain" (apex pointing upwards), you'll make a "valley" fold next (apex pointing downwards).
4. Make the second fold. Align the edge of the paper with the first fold, creating another crease. Try to make this crease as even as possible with the first.
5. Repeat steps 3 and 4. Continue flipping the paper over and folding, always aligning the edge of the paper with the previous fold. Each fold should be the opposite type (mountain or valley) of the previous one.
6. Continue until the entire paper is folded. Once you've folded the entire length of the paper, you'll have a series of alternating folds that resemble an accordion.

Essentially, you are creating a series of "mountains" and "valleys" in the paper, stacking them on top of each other by lining up each subsequent fold. With practice, you can make uniform folds for a neat, professional-looking accordion fold.