It looks like you're off to a good start and I like how I can see that you're simplifying the forms before adding detail, but I would say that the main thing I notice about them is that they seem to lack form and they have proportions that are off. I think what would help you the most would be trying to first build up the body of simple 3D forms (such as cylinders for upper and lower arms and the Same for legs, & something like a rectangular prism or a 3D tombstone shape for the torso, etc.) and not focusing very much on the outer contours of the form for now.
