Okay, little constructive criticism here. Don't freak out I'm just trying to help.
1st picture:
Minor anatomy issues that can just be attributed to style. That's okay as you do seem to have a basic understanding of human anatomy. I'd say work on varying your line thickness. Different fabrics are going to have different weights, thus they should be drawn differently to reflect that.
Also try working more with wrinkles in the fabric to add weight and depth to the different areas. You got a little of that going on but more wrinkles in the creases, especially in the armpit area and behind the knee area would go a long way. Along the small of the back for the coat and the waist area for the shirt and pants. The shirt could also benefit from a few wrinkles around the collar area too.
Shoes have creases in them as well, since I'm assuming based off color selection that those are supposed to be leather loafer styled shoes. Adding an area of contrast along the instep, where the toes connect to the main body of the foot would do wonders. Basically anywhere there is a joint there should be a few wrinkles to reflect that as the materials there wear out faster.
For the color scheme flats are okay but the shading is both subdued and inconsistent. Your light source seems to be coming from upper right yet your left foot is shaded as though the light source was upper left. Most of that foot and the lower leg above it should be shaded to match the majority of the body.There's a lack of shading on the face too, which detracts.
Overall a good picture with minor work needed to make it pop!
2nd picture:
You've got some anatomy issues here. First off your forearm is as long as your upper arm, with about a 20 degree separation between the two at full retraction. Currently the forearm is longer than the upper arm by about a fourth too much. Shorten it up a bit and the proportions will match.
Your hands are both too big, although the right hand seems a bit bigger. That could just be because it's still in the rough blocking phase. The perspective for them is a bit off, it's not impossible anatomy but it's awkward. Both hands out look much better facing forward more. Your right hand is at nearly a 90 degree angle from where it should be, left rotate inward about 40 degrees or so and it should be fine.
Now the legs. Your right leg, what's up with that? Our legs don't bend that way unless it's been dislocated. From the rest of the body's position we should barely be seeing anything below the knee. You could get away with showing a little calf and the side of one foot at most. Left leg? You have the right idea with the perspective you just clipped it a bit. Lengthen it out a tad and it will look fine.
I took your second picture and provided you with an overlay to show what I'm talking about. Your fist pic didn't really need it much and your third needs more than I'm willing to do.
3rd picture:
Where to start? First humans don't bend like this. The anatomy is terrible, classic shit anime pose. Knock this stuff off right now, until you get a better understanding of anatomy don't do this stuff. I can't salvage this one because you've already committed to screen tones.
This is a classic boobs and butts pose, an Escher girl if I ever saw one. Check out
http://eschergirls.tumblr.com/ for plenty of examples of what NOT to do regarding anatomy. You'll find this pose in there somewhere. I don't even want to do more with this one because I don't want to get mean, just know that this pose is all part of the learning curve. We all do these crappy poses and the good ones stop.
Everything on that last pic is painful to look at. We're looking at a corpse here, her neck is broken. Our necks don't comfortably bend that way. Either move her head to a side view or commit to the full body 3/4 view. Don't combine the two together, they don't work well together usually.
Moving downwards, we have one breast in side view with the second being reduced to a cancerous lump on top of it. Not to mention her arm is far too short. T-Rex arms ain't never sexy man.
Her back? is way too thing considering her barrel chest. Pick one: either she's a sexpot with a wasp waist or she's a realistic figure. Can't have both. Where's her ass? It's basically non-existent. There's also zero definition in her leg past the crease for the butt cheek. Knees indent from a rear view, even when standing straight up. The tendons stick out unless you are obese.
I'm sorry to be a bit harsh but the sooner you realize this pose is a bad one to copy the better an artist you'll be.
Hope this helps.