PHOTOSHOP CS4 DOWN & DIRTY TRICKS- P2
STEP 21: Make sure you still have the Move tool, then press-and-hold the Command (PC: Ctrl) key, go to the Layers panel, and click on the second and fourth layer groups from the top (as shown here). Press the Down Arrow key on your keyboard 10 times to move those two selected groups down a little from the rest (as seen here).
STEP 22: Now select all five groups in the Layers panel, then press-and-hold Option-Shift (PC: Alt-Shift), click on any one of the five groups in the image area, and drag straight downward to duplicate all five groups, creating a...