You've got pretty solid proportions and line quailty. Your ear looks amazing. Try pushing the differences in your values. Your neck looks like one entire color and I can only see a faint outline of a triangle where it might be a value change. The bright side of the face also looks like just one value. Be bold! Be dramatic! I did a quick overlay of your drawing. It's extremely rough but hopefully you can see the different values clearly. Side note: you also add a middle value under the nose to indicate a plane change. I hoped this helped some. Overall really good drawing, especially for a first attempt.