HOT KEYS

1) Menu

HOT KEYS - Menu
New Ctrl + N Open Ctrl + O
Save Ctrl + S Save As Ctrl + Shift + S
Export Ctrl + E Close Ctrl + W
Exit Alt + F4 Setting F5
Undo Ctrl + Z Redo Ctrl + Y
Cut Ctrl + X Copy Ctrl + C
Paste in Current Layer Ctrl + Shift + V Paste in New Layer Ctrl + V
Paste in New Image Ctrl + Alt + V    
Zoom In Ctrl + + Zoom Out Ctrl + -
Actual Size Ctrl + Shift + A    

2) Tool

HOT KEYS - Tool
Direct Selection V Move a copy of the selection Ctrl - drag the selected area.
Area selection tool select/change M Merge Selected Areas Ctrl + drag
Exclude Selected Areas Alt + drag Cancel Selection Ctrl + D
Select/change the crop tool. x 15 degree rotation Shift + Mouse rotation
Text T Increase font size by 1 point Shift + Ctrl + +
Decrease font size by 1 point Shift + Ctrl + - Bold Ctrl + B
Italic Ctrl + I Underline Ctrl + U
Align Left Shift + Ctrl + L Align Center Shift + Ctrl + C
Align Right Shift + Ctrl + R Brush B
Paint G Eraser E
Thickly ] Thinly [
Adjustment A Filter F
Scroll image with hand tool Spacebar + drag    

3) Layers

HOT KEYS - Layers
Hide panel F7 Duplicate Layer Ctrl + J
Add New Layer Shift + Ctrl + N Select bottom layer Alt + [
Select top layer Alt + ] Move the target layer up Alt + ↑(arrow key)
Move the target layer down Alt + ↓ (arrow key) Select top layer Alt + . (period)
Select bottom layer Alt + , (comma)