User blog comment:Sam Wang/How to Remove Background from Images/@comment-5040110-20130104102700/@comment-4316832-20130107123733

Honestly, that's pretty good! However, the green border around the head has been deleted and the borders aren't soft. It will be easier if the background has a better contrast with the tower's colour (e.g. doing the spectre on Z-Factor will produce a heavy contrast). You can adjust the hardness of your brush too.