Start with a rectangular sheet of paper
Fold the paper in half lengthwise
Unfold it
Fold the top two corners down to the center crease
Fold the new top edges down to the center crease again
Fold the plane in half along the center crease
Fold each wing down to form the airplane wings
Make both wings even and aligned
Adjust the wing tips slightly upward if needed
Throw the paper airplane gently forward