Refine the selection

In the Select And Mask panel, choose Onion Skin under View, and move the transparency slider to about halfway so you can see both the old and new background. Now select the Refine Edge Brush; with a medium-sized brush, paint over ‘difficult’ parts of the subject, such as stray hairs and fuzzy edges. Work slowly, giving the tool time to take effect. To clean up, use the Brush tool, which will add or remove areas depending on whether it’s in its + or - mode in the Options bar. The trickier the selection, the more manual work you’ll have to do. Using the Black And White mode in View will help you refine your mask.