Better Selections With The Refine Mask Dialog Box
When you’re creating selections, seeing the selection on the right backdrop can make the difference between a great selection or a bad one.
After creating your selection use the Refine Mask dialog box (Select > Refine Edge) to switch between different backdrops for viewing your selection.You can select the different backdrops from the drop-down menu, or simply press B for black, W for white, and K for a black-and-white view. There are others backdrops but these are usually the most useful.