First render - not bad. Second and third, your spotlights are too tight, or too close, causing drastic differences in how different parts of the figure are lit. Possibly back the lights out a ways and increase their intensity, or else increase their spread angle.
You might also benefit from a bit of rim lighting. Have you Googled "three point lighting?" The "back light" in 3-point can make a very interesting and subtle improvement. Even if you don't go with that, having lights from both sides of the camera produces what, at least to me, is more pleasing than a single spotlight.
Also, your shadows are pretty sharp. Look at the shadow line across the belly in the third render, for example. Are you spotlights set to "point" or "rectangle?" Using a rectangular light of reasonable size (30x30cm or 50x50cm) can produce somewhat smoother shadows and a bit more realistic look. No "real" light is a point - there's always some area involved. Basically, avoid "point" spotlights.