I stumbled upon instructions for making an origami star.
this one to print out.
I then followed these instructions to make a perfect pentagon from a square of paper, then these instructions to fold the pentagon into the star.
The resulting star is about 60% the size of the original square of paper. My square was 6" and the resulting star span is 3.7".
Make a bunch and string them up like a garland or alternate with pom poms. Here's where I got the idea.