Cut a long strip of coloured paper and fold it into equally sized sections, in a concertina pattern.
On a piece of plain paper, draw half of a Halloween design, such as a bat, pumpkin, ghost or spider, the same height as the strip of paper and half the width. [It must be something which touches the edges so when cut out in multiples will join together.] Fold this in half and cut out so that you end up with a symmetrical shape. This will be your template.
Place the template on the folded strip of paper. You may want to hold it in place with some masking tape. Carefully cut around the template, making sure to cut through all the folded layers.
Unfold the strip, which should now be a halloween garland with multiples of whatever shape you cut out. Repeat the process to get lots of them. Hang them individually or stick together with glue or sticky tape to make a longer garland. Attach them to walls or windows with blu-tack, scotch tape or drawing pins. Try making several in different shapes and colours for extra interest.