The shading on this image and the lighting perspective are breath taking... and her expression seems so timeless. Like a friend, with a knowing glance towards you. As if you've done some mischief that you can both laugh about. The line art and shading for her hair is slightly sketched, but smoothly painted. This fits well with the colors of the image, and how gently they seem to have been painted.
Over all, 5/5. Lovely work :3