I'm an Accident. I am your friend.

Here's what's going on. If one wants to pixel something believable, one must be aware of how it's actually-shaped.
As some posters above me have mentioned, even if it's obviously-stylised, it doesn't mean that you won't benefit from an anatomy study or two. Heads are not so round, eyes are not so big, we have knees, some barely lock 'em. We have elbows, and our skin creases. It heightens with cheekbones, it may sink with the actual cheek. Noses have nostrils, they're much more complicated than a wonky L. Bby, grab that pencil and draw your life away~
To me, it looks like you worked with each and every pixel. Perhaps used the line tool. That may be fine and dandy, but it's /not/ a good way to go about doing this if you're a newbie. When I began doing any form of graphic, be it pixel or PS'd, I would sketch out the basic shape, how the character looks like, and overall its feel. Most of my bodies are actually made out of random squiggles I jot down at first. The beautiful thing about the human eye is that it sees the 'lines between the lines' and leads you to thinking in different ways, different perspectives.
Okay, so, about your piece. Is he an old man, or a young man with a long, achromatic beard? He has no wrinkles, no fold, no distinction from a younger person. Why give him the Beard of Rasputin if he's not Rasputin himself?
I attempted to construct an old wizard the same way I suggested for you to.

Old men usually crouch. Their limbs are distinctly bony. I'm not... really good at describing much. But with resizing (no anti-alias, mind you), colouring, and fine-tuning, you can eventually get this:

It's POTION TIEM!
C: Welcome to Pixelation.