i dont mean to be mean, im trying to help. apologize in advance if i offend you.
okay lets start with facial shape:
there is lines in which you should place in to get the correct shape. especially in realism drawing.
look it up on the net if you need to, search and look at how the face is shaped.
thew one you have draw is a pit large on the neck side and the ear is placed to far back. a head should be more of an egg shape in size and then adding the extra bits on to it.
okay on to the Neck:
the neck is draw wrong for this picture its a bit to large and on an odd agnle, it doesnt help that the head shape is wrong. once you fix the head shape work on the neck.
now for eyes:
the eyes, to start well he looks very cross eyed, it need to be fixed so that he is looking in one direction and not 2.
also one eye is very lop sided and they don't go along the eye lines which you will find out about once you look up the head shapes on the net.
which will make everything in proportion.
on to the nose:
the nose is to thin for his face as well as to long and makes it see as if it doesn't belong there. everything in the face has to seem like it all fits together like a puzzle.
the mouth:
is to far down his chin, it looks as if he doesn't even have a chin, it need to be moved up ward and closer to the nose. so at least he will have a chin. also this will help once you get the face shape right.
Hair:
the shading and detail on the hair is great and keep up on those details.
Body: as you cant see much of it i cant say much here at all
but i hope this helps you and keep drawing, as long as you enjoy it who cares what other people think just put your heart and soul in to a piece and it will be perfect for you.