If I may be so bold: You need to work on the facial structure. Right now, it's fairly bland and flat. It needs to be pushed outward. As for the first picture, the hair was. . Odd, to say the least, and it looked like it was pushed off to the side too much, making the face look disproportionate to the rest of the body.
The second picture had the same problems. That, and it looked like you put way too much emphasis on his stomach, making it look sloppy and unappealing.
I will say that I liked the female picture, except you need to work on your shoes.