Remember that the outlines are always only one pixel thick, but that's a common mistake with beginners. In the lighter areas you might wanna replace the black outline with a lighter coloured outline. The shape also needs a lot of improvement in some areas like around the head.
I do sense a noticeable light source though, good job on that.
The eye on the first one is well done, but the second has to be more round-ish. Try using the circle tool to help you with that.
Remember to take your time and improvement will come faster than you think ^^;