I digitally "painted" with a brush in thin layers, just as if I was painting traditionally. I did have to play around with some different brushes before I found the one that worked. The bonus of working digitally is that you can delete a layer if it doesn't work.
I debated between adding text or leaving it "empty". My husband thought of the text, and it was better than the nursery rhyme I was going to go with. The added text definitely makes me giggle more than with out the text, and it basically summarizes the nursery rhyme in one word.