I tried everything under the sun and looked at almost every YouTube and video on the net to learn how to do a decent extraction. I don't care what I did or how much I followed the step by step procedures, my image would always turn out to have the fringes.
I found a technique that I use that really works for me; opposed to the Pen & Extraction tools and that is.... THE POLYGONAL TOOL
What I do is use the Zoom tool and zoom in on the image until I can see the Pixels on the edge. Usually, you can see ripples around the edges of the images--that's what the cause of the problem is.
I use the Polygonal Tool right on the edge of the pixel area; taking off little bits and pieces at a time. Even around the hair, I can see the pixels and take that off bit by bit.
I may just do a tutorial on how I do it .. because now, I can render ANYTHING using that technique.