Start by painting your styrofoam balls. Painting something that rolls is a pain in the arse but I found an easy solution if you're spray painting is to place it on a solo cup and do one side at a time. I really love the red because it pops through the corks but feel free to use any color that works with your decor!
Once you've filled the entire ball you are finished! Told you this was so easy. You can do this in an afternoon. The longest part is waiting for the paint to dry... which always drives me nuts.
If you want to add a candle just buy a small tea candle and use an xacto knife to cut out some of the styrofoam ball. Glue the candle holder in and then start doing the corks from there.
I was totally planning on making another big ball but ran out of corks! I underestimated how many it would take. Just another reason to pop some bottles, am I right?!