When you're drawing, make sure that you rotate the head along with the face when the subject is looking over to the side. The second drawing, of the policeman, has his face turned to the side, but his head appears to continue facing forward. I think your third image is rather well done, you seem to have a good mastery of drawing someone from the side, but the problem is that this is a very flat view, and doesn't accurately reflect most poses (such as a 2/3rds rotation of the head, like you have in the first image.) The toughest thing I've seen people have had to cope with when drawing humans are feet and hands. I would recommend practicing those more if you can.
Practice, practice, practice! It seems like a decently good start so far, so just keep on going.