This isn't necessarily an Excel Tip, but this is still helpful.
Anything to shave a couple seconds from your work day. Of the below, I use the 'windows key + M' shortcut the most.
1. Ctrl + Drag File
Makes a quick copy of the file/folder
2. Windows key + M
Minimizes all open windows
3. Alt + double click file/folder
Pulled up the 'System Properties' dialog box