You can also use chalks. I did some cards recently with the sparkly chalks, and they are sooo beautiful! Use a swiffer floor duster dry cloth to go over and collect the chalk that gets "outside the lines". It's perfect. And the SU white gel pen is the best there is!!!
Try this link...
http://karenbarberstamps.blogspot.co...&max-results=7
and scroll all the way down. She does these sooo well! Hers are done with SU pure color pencils.
There is also a tutorial on the resources page.
Good luck. This is a wonderful, and addictive, technique! I love it.