try defringing the layer if you dont know how to then ill show you layer>matting>defringe and then select 1 to 2 pixels that should lessen the jaggedness and such a little bit but not very much
Using paths is much more effective and maintains a much purer quality. Just use the pen tool to draw over the render, select the paths tab in the layers box, hit 'make selection' and cut out the original render.
That effect basically serves the same purpose of making it look like it was cut-out improperly. It also makes the chief stand out more, whereas for that sort of thing you'd probably want the chief blending into the sig a bit.
lol...how can it improve? I tried using the same effect as the picture i showed you guys. I also spent more time cutting it out but there are are few errors.