First, you should read up on basic face shape. Barring physical manifestations of trisomy, people's faces are not that round. The face generally tapers to the chin and all that. In a 3/4ths view (which is what you seem to be going for,) there should be a visible brow, a slight drawing-in of the skull where the eye sockets are, and visible cheekbones. In addition, the nose doesn't generally go past the brow unless you're a space monster -- the nose merges with the brow. Look at yourself in the mirror and try to memorize just how your skull is shaped -- try to create a 3D picture in your mind, and that'll come in handy when you try profiles and other angles.
Secondly, his hair is ridiculous. It looks vaguely like what might happen if some spoiled white kid tried to give himself dreadlocks with only a vague description of what they look like, but I don't think that hair like that is possible by any means. Aim for less ridiculous styles and I'm sure you'll be a little better off.
Third, where are his ears?
Fourth, the nose and the eyes seem strange in proportion to the rest of the face. Eyes generally don't taper like that -- again, look at your eyes. Notice how they taper slightly on the inner side, and are rounder on the outer side. The nose is just a perspective problem -- the way you have it drawn and shaded, it looks like the nose is facing to the left side of his face, and is closer to his right eye than his left.
Fifth, make your shading gentler and more gradual. This sort of two-tone shading looks pretty bad. Remember, you can make practically any shade from black to white so long as you don't smoosh your pencil right into the paper.
Oh, and sixth, turn up the contrast on your scanned drawings a little. It's really tough to see the fine lines.
Oh, that reminds me! Drawing lines! I'm not sure if you're doing this already, but I usually find it easier to draw by making a series of strokes instead of just pressing the pencil in for the entire line length. But then, I'm sure that it's just a technical choice, and that other people might have different methods. Just stick with whatever gives you a good result.
