Lil' anatomy crit (you could chalk the difference up to style but I think it would look better if the anatomy was more correct) -- his hands should hang down to about halfway between his waist and knees.
It is a solid beginning. I like it =) It doesn't have that flair of excellence -- but unfortunately, none of my stuff has that flair either, so all I can do is advise you to keep searching. Look into shifting some colors around, because right now they look alright, but they aren't going to "wow" anybody.
(I also agree that the post could be more interesting -- he looks a little like a plastic action figure right now...one of the ones without bendable joints).
As for nervousness -- you put forth a good effort, and there's noticeable improvements in your edits. You don't have to be a magnificent pixel artist in order to be an asset to the forum. Not a single thing to be ashamed of in your art or your attitude =)
Things to fiddle with: try using colored outlines *inside* the sprite instead of black ones (like at the shoulders and waist and neck) and try using some sharper shadows (there's a subtle top-left lightsource right now, but I think you could give it more depth). Not saying those things WILL be better, but they will at least be good practice ^_^
