The cloth folds were very good and added to the richness and realism of the figure but with the light coming from below on to the figure the highlight of the fold might better have been below the shadow rather than above. You can also add to the realism of the cloth with some judicious use of the "Liquid Tool" in Photoshop to raise bumps of fold on the edge/shilouette of the cloth.

For integrating the background to the figure you can do a little median from the noise filters to smooth the image to agree more with the render. Sometimes anisotropic diffuse from the stylize filters works. The hue/color cast can also be shifted to match the temperature of the figure... here you figure is warmer and higher saturated than the background. Sometimes you can help create the illusion of a good composite by applying the Photoshop render "Lighting Effects" to match the Poser lighting on your figure. I also tend to brush a subtle blur set to "darken" along the edges of the rendershapes where they meet the background... softens the edge and gives a sense of volume.

I do not know if you are placing the background in Poser or Photoshop but you know how to make a selection mask in Poser? You save your scene as a .pz3 first and then go to your figure and clothes or whatever you want to issolate and set the diffuse value to zero and the ambient to 1.0 with a key color like pure blue or green and then delete all the lights using the python in the script menu and render.