If the subject is on a bright background (or at least around the subject's silhouette) a good way is to apply an image into its own layer mask, then you can play with level/curves to adjust the 'Fuzziness' and dodge/burn to separate the transitions a bit better too. You can even choose what channel (R,G or B) to go into the mask to get better separation.
I dont get on with the extract tool at all, for me it makes edges all broken up, and its just doesnt work out for me, i'm probably doing something wrong.