I have to put in a good word for ink and colored pencil as rendering media: ink lines give crisp definition, detail, and copy well, while colored pencil is fast, colorful - bold or subtle as desired - and wonderfully erasable when you goof. More forgiving than theater-traditional gouche or watercolor!
Here's a different ink/pencil rendering for a kids' Easter show at Casa Manana a few years back - a fast-fast-fast sketch. Try it yourself.
Like crayons, the bigger the box of colors, the more fun!