Gday Paves
From what I know about anatomy, the ears are pretty spot on location wise. Maybe a slight twist of the whole ear so the top is further back ie. the left ear should be rotated a little clockwise in your first pic...But Gawd, ears are VERY complex, even to draw...
The jawline should be more pronounced, with the area below the ear and the nape of the neck below the skull edge to be thinned a little to help this... As a general rule form what art classes I went to, the eye line should be approx. halfway from tip of the skull to the chin, which would mean building the top of the bonce a bit more...
AS you said, this was your first effort, and quite commendable!
Had a thought~ Do you have an action man doll or similar? This would give you a good 3D rendition to view...
Keep up the good work
Cheers
Brad