Here are a selection of Shortcut Keys for use in photoshop (some in Manga Studio) that i use on a near daily basis.

The basics:

Ctrl+A Select all

Ctrl+C Copy

Ctrl+V Paste

Ctrl+X Cut

Ctrl+D Deselect

Favorites:

[ and ] increases/decreases your brush size

Ctrl and + or - is zoom in or zoom out

Ctrl+F apply last filter

Ctrl+J create new layer via copy

hit / to make the layer lock transparency

Alt + Del - fill with foreground color

Alt+lasso click - When using the lasso tool, instead of going micron by micron and stressing about it, you can switch the setting to magnetic lasso by holding “alt” when clicking. That way you can go by points you click instead of developing carpal tunnel slowly selecting things.

Shift + lasso adds to a selection

alt + lasso (prior to selecting) will make it unselect or cut from a selection

D by itself reverts your color selection to black and white

Ctrl+N new image

Ctrl+Shift+N New Layer

Ctrl+E merge current layer with one below

Ctrl+Shift+E merge all visible layers (if your base layer is not called background you will have to manually flatten in the layers if saving as a JPG)

and of course

Ctrl+S to save

and my all time faves

Ctrl+Z to Undo

Ctrl+Y to Redo

I have my tablet’s (I use a Intuos btw) top button set to keystroke Ctrl+Z and the one below that to Ctrl+Y as a time saver.  The front button on the stylus is set to erase which I find is very convenient.