Random sketch

Nice job on this one, it's very similar to the one with the tan background. The first thing I notice is the hair. You've got the flow, now you need the mass. Think of hair more in the line of lumps of clay. I know that sounds odd but hair is usually less like line and more like shapes. It needs shading too. I love the cheeks bones I think their my favorite feature and the chin is quite believable.

Keep going darker then go in with an eraser for the highlights. I'm detecting marvelous potential in fact I'm quite impressed you've managed to develop this far. It took me ages to figure this stuff out.

Go darker then bring back the light. Don't worry about making anything perfect. You might be surprised.