I'm glad you liked it :) So, what I did was
1 Draw the butterfly
2 Outline it
3 Fill the black color
4 Shade the design using oil pastels
Now for the background.
Take the color. add a few drops of white to it. and do the base color. let it dry. Now take the same color (without white) and put a few drops of the color on the place where that color is starting. add some water. and let it flow. (do it cautiously, the other pages might get spoiled)