first is not good, you covered Yoru's face with the C4D, erase parts of the C4D to give more attention to her face, save it as PNG from File > save for web and devices
Lol at the second one
Third is simple, and ok
I dislike the fourth one, you didn't do well in smudging the edges for the render, you made it look messy, try to be careful while smudging the edges to make the render blend within BG, also try to use the clone stamp tool better, IMO it wasn't pretty nice, and lightsource isn't so clear, use a 200 px soft white brush put it in the same place the current one is place, if it's too clear, lower the opacity.