It's not bad, but it looks like parts of it were done in photoshop. The lighting on her boots doesn't match up with the lighting of the couch, and the background doesn't look like it's actually /there/, if that makes any sense (like you had a greenscreen, put some gaussian blur on the background and just chucked it in behind the window). If the photoshopping was done better, this would be an amazing shot. Also, the model doesn't look as if she is actually on the couch; although there is a 'dip' where here heel is pressing into the couch, there doesn't seem to be any where she is located. Like I said though, good idea - just needs practise.