Sometimes it would be better to prefer keyboard to mouse, as it saves a lot of time. Here is the list of most common “time-savers” for Mac OS.
• Command+O – open a window
• Command+P – print the document
• Command+A – select all items
• Command+Z – undo the action
• Command+S – save your work
• Shift+Command+S = Save As
• Command+W – close the open window
• Alt+Command+W – close all open windows
• Command+J – make the icons larger (works when the Finder is open)
• Command+Q – quit the program
• Command+C – copy
• Command+V – paste
• Command+X – cut
However, each app on your Mac has specific shortcuts. As a rule, you can see them near the menu item