The ear looks really good! When you trace over your picture, what percent opacity do you put it at? If it's not around 20-18% I'd suggest doing that so you can really see your drawing as you trace. I'd also suggest using thinner lines, like 3-5.
For shading the nose remember the pyramid shape. The bottom of the nose should be close to flat with the wing of the nostril around the same level as the middle of the nose. I think you had a pretty accurate structure for the drawing, but it was lost a little after the shading.
For the lips try to make the guidelines curved even the face is looking straight-forward.
Also try to push the curve for the side of the lips more. Imagine them curving around a cylinder.
It's not the greatest thing I've done, but it helps explain the shape of the lips:
These are notes I took from one of Istebrak's videos