First of all, when doing some character you need characteristics

Yeah, I know it sounds stupid. But right now your guy is just a button with cross-eyes. Are those intentional? If yes, then try to make it look that is intentional, and not like you just mirrored them. The same thing happens with the rest.
If you don't know how to make arms and legs (like myself

), then don't put him some smileys extremities. Again, unless that's what you are going for.
Better concentrate on the head for now, and then add the rest.
Also, the shadow you gave the head made it look like a clickable button. It seems that if your character would turn, it wouldn't be a sphere, but a square.
This is a quick edit I made:

In conclusion the most important thing you need is to know what you're going for. If what you are going for is just practice, then as Lizzard said learn from looking at other people sprites.