Control/Ctrl is the same in Windows as the Command/Cmd/Apple key is for Mac; Alt for Windows is the same as Option for Mac.
General Computer Commands:
Undo: Ctrl + Z
Save: Ctrl + S
Print: Ctrl + P
Toggle among applications: Alt + Tab (Cmd + Tab for Mac)
Select All: Ctrl + A
Copy: Ctrl + C
Cut: Ctrl + X
Paste: Ctrl + V
Open: Ctrl + O
Open Windows Explorer: Windows + E
Photoshop Keyboard Commands:
Fit on screen: Ctrl + 0
Deselect: Ctrl + D
Hide edges: Ctrl + H
Crop tool: C
Clone stamp tool: S
Zoom tool (magnifier): Z
Move tool: V
Increase brush size: ]
Decrease brush size: [
Zoom in: Ctrl + +
Zoom out: Ctrl + -
Step back in history: Ctrl + Alt + Z
Step forward in history: Ctrl + Shift + Z
Reselect: Ctrl + Shift + D
Inverse: Ctrl + Shift + I
Adjust levels: Ctrl + L
Adjust curves: Ctrl + M
Adjust color balance: Ctrl + B
Adjust hue/saturation: Ctrl + U
Layer via copy: Ctrl + J
Combine layers into new, added layer: Ctrl + Shift + Alt + E
Last filter: Ctrl + F
Show/hide rulers: Ctrl + R
Fill with foreground color: Alt + Backspace
Fill with background color: Shift + Backspace
Switch foreground/background colors: X
Keyboard shortcuts are a way to access controls in Photoshop by using the keyboard. These shortcuts truly save time when you're working in Photoshop. It takes a lot less time to press Control or Command C, for example, compared to going to the Edit menu and then finding Copy and clicking on that. Or you can select the Brush tool with B, then make it smaller with the "[" key and larger with the "]" key.
Photoshop has many keyboard shortcuts already built into the program. In addition, your computer has a whole set of keyboard shortcuts that work in all programs, including Photoshop. The "built-in" shortcuts are a great place to start, and some of the most useful are shown in the chart on this page.
In the keyboard shortcuts dialog box, simply go to an application menu command and click on it to show available controls in that menu. Select the command you use frequently and type in a new shortcut key combination. If this shortcut is already in use, Photoshop will tell you, but you have the choice of deciding how you use your keyboard.
For example, I like to set up keyboard shortcuts for Unsharp Mask and Gaussian Blur. I make it easy and use the F2 key for Unsharp Mask and the F3 key for Gaussian Blur. Both of these keys were already used for other commands, but I never used them. So I appropriated those keyboard shortcuts for myself.
Since adjustment layers are a big part of my workflow, I set up keyboard shortcuts for adjustment layers. I use Shift + Ctrl/Cmd + L for Levels, for example, and Shift + Ctrl/Cmd + M for Curves.
Actions are a cool part of Photoshop, and using them can speed up commonly done tasks. Actions are like a recording of whatever you're doing to a photo-a recording that can be replayed at any time and the exact same adjustments will be applied to a new photograph.
Make sure your Actions palette is open (if it isn't open, go to the Window menu to turn it on). Next, in the Actions palette, make sure there's a check in the box next to Default Actions. To see how Actions work, experiment with a few in the Default Actions folder. For example, select Sepia Toning and then click on the play button at the bottom of the palette.