In the main menu, select "Art School".
From the list, do "Sketch a Tomato", "Gesture and Contour Drawing", and "Garden Grid". You can do them in any order. The achievement should unlock after you do the third lesson.
You don't have to do everything the tutorial says, just do a little line or whatever at each step. I don't know if it's necessary to save the drawing from each lesson to the gallery, but I did it anyway.