Enhance selection

To enchance a selection choose from the following actions:
Selection tools options

Select any selection tool and use the tool's options as follows:

Move selection border

To move a selection border choose use any one of these selection tools and select in Tool's Options palette mode to New.

Masks palette

Using masks is one of the best ways to improve selection quality.
Learn more...

Refine selection

Edit ‣ Refine Selection
Option ⌥ + Command ⌘ + R

Click to reset values.