Render doesn't seem to be the main focus because of lighting here, since this is a smudge signature. Smudges are fine, but make it so there are main points among them, not all of them to be all the main points. Put some lighting spots into it, to make some parts brighter than others. Also, render isn't blended as well as you would like. Try making a layer above the render and smudge a bit near her edges to blend it in together.