Shortcut Photoshop

Going beyond the basics
Now you know a decent set of basic shortcuts used in your everyday work, e.g. T for Type tool or C for Crop tool, it's peak time to take your Photoshop experience to a completely new level learning a bunch of new shortcuts that, I promise, will surprise you turning out to be extremely handy and useful.
I grouped the shortcuts into topical sections, so that you can easily find shortcuts for Tools, Layers, Effects and so on.
If you don't find a shortcut here you know yourself and think it could be useful for other readers, 

Photoshop Keyboard Shortcuts:
Move tool == V
Marquee tool== M
Lasso tool == L
Selection tool == W
Crop tool / Slice tool == C
Eyedropper, color, ruler, count tool == I
Healing / patch tool == J
Brush / pencil tool == B
Stamp tool == S
History brush tool == Y
Eraser tool == E
Gradient tool == G
Dodge / burn tool == O
Pen tool == P
Type tool == T
Path selection tool == A
Rectangle / line / shape / elipse / polygon tool == U
3D manipulation tool == K
3D view tool == N
Hand tool == H
Switch secondary tool of the currently selected tool  == Shift+Tool Key
e.g. Shift+U
 
Working with layers shortcuts
Create new layer == Shift+Ctrl+N
Copy (duplicate) selected layer == Ctrl+J
Merge current layer down == Ctrl+E
Delete currently selected layer  == Delete Key
Fill layer with selected foreground color == Alt+Backspace
Remove color information from layer == Shift+Ctrl+U
Instantaneously create new layer (with standard parameters) == Shift+Ctrl+Alt+N
Select next blending mode for layer == Shift+ "+"
Select previous blending mode for layer ==  Shift+ "-"

Working with Groups shortcuts
Create new group from selected layers == Ctrl+G

Working with Masks shortcuts
Switch to Quick Mask mode == Q
 
Color selection shortcuts
Toggle background / foreground colors == X
Reset default colors (black and white) == D

Selection and areas shortcuts
Fill selection with current color ==Alt+Backspace

Program windows and views shortcuts
Hide / unhide all windows but project window ==Tab
Hide / unhide right-hand side Photoshop windows == Shift+Tab

 

Source:faqbay.com