Selection Tools
There’s quite a variety of tools available when you need to grab a specific area. For instance:
A) Rectangular marquee, elliptical marquee, single row marquee, and single column marquee
B) Standard lasso, polygonal lasso, and the magnetic lasso
C) Magic Wand and the improved Magic Wand tool (which you'll find exclusively in CS3)
Deselecting
If you need to clear your selection, there are two straightforward ways to handle it.
A) Simply click your mouse anywhere outside the active selection
B) Use the keyboard shortcut CTRL+D
Rectangles and Ellipses
Creating a rectangle or an ellipse is pretty intuitive. If you're aiming for a perfect square or a flawless circle, just hold down the Shift key until you release the mouse button.