Tip 4: Your Menus, Your Shortcuts
When changing keyboard shortcuts, Photoshop will alert you if your proposed shortcut is already in use.
(Click for Full-Res)
You don’t have to see every menu item Photoshop offers. To pick the ones you want, go to Edit > Menus. Then click the eye icon to hide a given item. You can also create or customize your own shortcuts—click the Keyboard Shortcuts tab to edit them. Choose the menu item you want to access faster, and type the keyboard command you want to use to activate it.