Theres a little green spot on the top left of the sig that looks outta place. Maybe try incorporating a slight amount of depth to it? Looks really nice tho Good job
nice. I would say avoid centering your focal. and 'gas mask' guy is a bit poor quality although nice start for c4d. you can get nice quality cut out renders off planetrenders.net. your latest singature looks sick man keep it up.
the gradient map(im assuming is what you used) that you put on top of the entire signature drained a ton of the color from the actual render try using more effects to help blend your render into the sig especially on the right side of her hair where the image was cut off .. your text and border are kind of on the large side
do one of these tutorials for me step by step and lemme see whatcha come up with ok?