On the shade side of the stamped leaves, I added a dark brown line and on the light side, a white line to accent the shapes.
You can find paint pens over by the Patio Paints which they usually keep by the terracotta pots in the silk plants area at the craft store.
The zebra area is just freehand, but the spots next to it are done with a stamp. Also notice how I used the paint pens to make nice straight lines in between each different area. Please let me know if you try one for yourself, I'd love to see it!