After drawing in pencil they "traced" the pencil with white glue. I love using this technique! The glue resist gives awesome black outlines and "borders" for the chalk which is done the following week. The kids love to trace with glue. What can I say?!
The following week I gave them all sorts of colored chalk (we prefer the Crayola chalk- the colors are SO vibrant and show up so opaque on black paper!!!) and they went to town. Some kids wanted to keep the lizard sort of "life-like" (read: greens and browns) while most kids wanted to go wild with pinks or blues. Either way, they turned out fabulous and they were the talk of the school whilst hanging on bulletin boards!
While the chalk is VERY messy, everyone just loved how they came out and didn't mind a little mess at the end :)