Take it outside and spray paint it black. In this picture it looks white but that is just the lighting because I was actually using black paint.
Here is a tip I learned the hard way. I started by fanning my wreath out how I would want it when it was finished and then started spray painting but I kept have to go back and paint some more and more because I would find a place that was tucked under some where. So instead start by standing all the pieces up straight and then spray paint front and back and from the sides and you will waste less time and paint. Also if you want it to be more shiney use a glossy finish spray paint. I used elcheapo flat spray paint so I added a few sprays of glitter while the paint was wet.
Last tear 1 inch strips of fabric in Halloween colors (length doesn't matter because you will be able to cut them) and tie around the wreath. I kept a pattern but that isn't even important either. You could add spiders or bugs or anything else you would like to jazz it up. I left mine just like that and I think it looks pretty festive.