It this your first piece ??
Congratulations. We'd probably love to hear about your artistic background

About the piece itself, I think the white outline is jaggy, it deserves antialiasing or a trip to the recycle bin.
The main problem I think is that the character seems to be sitting on an invisible chair and that he's going to collapse in a moment.
Also, light blue colors inside the pants dont make much sense to me, I think it should be dark all the way and that legs should partly be in the shadow cast by the pants.
Face probably needs work too but I'm not too good on that so I'll just pass.
Otherwise, good work, especially if it's your first (hardly believable actually

).
Oh and welcome to Pixelation.