Shortcuts I Use
Using shortcuts in Photoshop makes work faster and you feel witty when you use them. Here's a list of the ones I use very almost every time I make something within Photoshop. As a Mac user, I'll list them as "Cmd + _" but command is control for Windows users.
Cmd + D= Deselect
Cmd + Shift + I= Invert Selection
Cmd + Alt + C= Canvas Size
1, 2, 3, etc.= Opacity 10%, 20%, 30%, etc.
Cmd + Alt + Z= Undo
Cmd + Shift + S= Save as
Cmd + S= Save
Cmd + Shift + E= Merge Visible
My favourite shortcut: Cmd + Alt + Shift + E= Merge visible on new layer
I hope you find these as useful as I did! Got more useful shortcuts? Comment and I'll add them in.
-Swiftex