It's hard to do a composition with just AN artichoke, so I tore off a couple of leaves from the backside and used them to set up a simple composition.
This first photo is the color of the 9 x 12" Colorfix paper. It's supposed to be a dark gray, it looks a little blue here. I have drawn my Dynamic Symmetry grid and found the lower right mean (see the tiny little mark?) My focal point (the lit side of the artichoke will be placed along that line. The small leaves are placed on one of the DS construction lines. This is believed to make the angle/the painting more pleasing to the viewer in terms of composition.
Dynamic Symmetry Grid with Right Mean Identified
Using NuPastels I have sketched in the major shapes of the artichoke and it's leaves. Starting to lay in the darks.
Here I have the major shapes in and have been laying in color, constantly tweaking the shapes. You can see that the top right of the artichoke will be mostly in shadow. I got tired and lost focus today before I could get to the artichoke...will have to tackle that tomorrow.
Although I work from life and thus my viewpoint is a bit different than what you see here, it does give you and idea of what the setup looks like.
Photograph of Artichoke for "Artichoke Tuesday - A Study"