Often, a selection tool will select too much, such as the Magic Wand tool.
You can use the Selection Brush tool to "mop" the excess selection away.
Be sure to check off as you go along.
First, you can make the selected area stand out.
The selected area remains normally colored.
The area that's not selected turns red.
You can change the color in the Overlay Color box.
Increase the Overlay Opacity to make what's selected stand out even more.
Now you can mop away what's not needed from the selection with the Selection Brush tool.
3) Make sure the Add to selection button, in options bar/Tool Options, is selected.
What you do next depends on whether the overlay is being used.
If you're using the Mask mode (red overlay), do the following.
As you paint, the unneeded areas will change from "clear" to red.
If you're not using the red overlay (Mask mode), do the following.
Pressing and holding Alt makes the Selection Brush tool subtract from the selection.