This keyboard shortcuts will massively improve your speed and efficiency while working in Photoshop CS6.
CTRL + N
Create a new document
SHIFT + CTRL + N
Create New Layer
CTRL + Backspace
Fill a layer with background color
ALT + Backspace
Fill a layer with foreground color
X
Switch the foreground and background color swatches
CTRL + A
Select All layer
CTRL + D
De-select All layer
CTRL + [Current layer thumbnail]
Select current layer
[ or ]
Resize the brush tip
ALT + arrow up/arrow down
Increase/Decrease line height in type mode
ALT + arrow left/arrow right
Increase/Decrease letter spacing in type mode
Space bar
Temporarily switch the current tool to the Hand tool, for moving around the image while zoomed in
H
Select Hand Tool
CTRL + I
Invert the color of a layer mask
CTRL + ATL + Z
Undo the last change multiple times
CTRL + T
Activate the free transform tool
CTRL + J
Duplicate the current layer
CTRL + G
Group selected layer
CTRL + E
Merge selected layer
CTRL + S
Save Document
CTRL + SHIFT + S
Save as Document
ALT + SHIFT + CTRL + S
Save for Web
F12
Revert Document to initial/opened state
