Here is a list of quick useful shortcuts while working with files (Command - W) is most important for new switches.

1) Open a file: Command - O

2) Get information about a file in the Finder: Command - I

3) Save an open file: Command - S

4) Save a file to a new location Command - shift - S

5) Set save Location to the desktop while in the save dialog box: Command - D

6) open the print dialog box: Command - P

7) open the page setup dialog box: Command - shift - P

8) Close an open file Command - W