Draw with crayons on paper. Draw shiny and bright. If you have oil pastels, they work really well for this project too.
Spray liquid watercolor paint over the crayon drawing, and before it can dry.
scrape the paint with a spatula to spread and dry it. (You can also use a credit card or ruler to spread the paint.)
The bottles that I use that work best are from Discount School Supply and make a fine controllable mist, not a wide spray like some. Liquid Watercolors come in amazing colors, including metallics. I love them more than any other paint I've ever used.