Hey, this looks pretty good! There's a few little problems with proportions, and also the geo in places could be collapsed/ redirected... Nothing too bad
I was working on Low-Poly characters for awhile, about 8 months ago for a small Unreal Mod that died (sigh..) , but anyway.. during that time I collected a bunch of references form, wire frames images of models, to photo references, to orthos. So let me know if your interested, and I can zip some stuff up for ya, and send it your way!
Anyhow, nice work so far!
www.stevenegan-cgi.com
"Your weapons are no match for ours! People of Mars, surrender!"
"Um, this isn't Mars. This is Earth."
"Earth? Earth-with-nuclear-weapons Earth?"
"Yes."
[long pause] "Friend!!"