Group and Ungroup – Similar to using a track matte. Apply a layer to its downstairs neighbor, but only in areas where there is opacity. This is often used to constrain a fill layer to a lower text layer for a Paste Into effect. It is also used internally by many layer styles to create proper clipping for bevel effects.
Group: Cmd+G (Ctrl+G)
Ungroup: Cmd+Shift+G (Ctrl+Shift+G)
Arrange Layers – You can move layers around from the keyboard.
Bring to Front Cmd + Shift + [ (Ctrl + Shift + [)
Bring Forward Cmd + [ (Ctrl + [)
Send Backward Cmd + ] (Ctrl + ])
Send to Back Cmd + Shift + ] (Ctrl + Shift + ])
Align Linked and Distribute Linked – Because your eyes aren’t that good. Link the layers together and access these controls from the menu (or use the Move tool and Options bar for a graphical interface). Want something centered on the screen? Link to the background layer and highlight it. The highlighted layer is the basis for all centering and distribution.