That’s exactly how my “Thar Be Treasure” wallet for Dynomighty evolved: it started off as a simple drawing, as you can see in the bunch of ideas. Hint: it’s in the middle! I then started designing directly in Illustrator with my beloved blob brush, playing around, trying different versions of the cartoons, and paying little heed to any constraints of the artboard:
There is no right or wrong way to work—it’s all personal style! Go out there and do it! Keep those hamster wheels churning!