Looks like your model will have moveable eyes and mouth is that so? By the way it’s a good start.
Here's a rule of thumb for low poly humanoid characters if your limbs and shapes in general have 4 vertices in circumference = approximately 1000- polys, 6 verts cerc. = approx. 1500 polys, 8 verts cerc. = approx. 2000 polys. 8 polygons around makes a more pleasing natural shape for an arm leg or torso.
