For those that wonder how much time I spent on this sketch I think it's something about 20 minutes... (I kinda seemed not to decide if I wanted long or short hair... I tested some others yet decided for the long one... as always )
The program I use to sketch is called Corel Painter IX. I mostly use the 2B Pencil tool and the Details Oil Brush 5 tool to do the lines. the size of the tool vary according to the zoom in/out I'm using.
I usually start with a 1500x1500 pixels size 72dpi resolution and add sizes to it if needed. (like I had to make space to draw his hand... )
I'll probably re-size it to a bigger resolution if I decide to do a better lineart and paint it with the same tools and program I mentioned above and also the grainy water tool for smudge if needed.