Nice! Don't color w/ markers though
Suggestions:
1) add some depthy... the torso position has a li'l', but the face is quite flat (the mouth has no right half basically, the teeth on that side wouldn't perfectly match up with the left half)
2) Define the form of the collar-ish thing a bit more. As it is, I'm not sure if it is a collar type metal thing or if it's part of that brown section on the front of the torso... Right now because the top section of it, the lighter gray section, doesn't continue there, it looks like it melds into the body.
3) Is the brown area part of the body, or a garment of some sort? Right now it appears to be part of the body, but (2) make it look like it melds into the collar. If it
is supposed to be a garment, add a little bit of detailing, maybe just a line of stitching down the side. (Pretty sure it's not supposed to be that though :))
4) Shading. Not necessarily an actual necessity, depending on what you're going for. That's why cartooning is great :D.
Things I like:
1) The eye is tight, especially the squinting effect implied by the stress under it, and around the upper lip.
2) The anatomy is decent, yet cartoony.
3) it actually looks like it's snarling.
Anyways, because it's colored in marker there's not much re-doing you can do, but I look forward to more drawings in the future! You better post some.