1. Open a Finder window
2. Click on View on the Finder Menu
3. Click Customize Toolbar to display the customization window which indicates that you can "Drag your favorite items into the toolbar ..."
   
   
   
   
   
   
   
4. Drag whatever you like into the empty box about the customization window
   
   
   
   
   
   
   
5. Click Done when you're finished with your selections
   

Note:

• You can save mouse clicks by simultaneously pressing the Command and Option keys while you click on the Toolbar Control button
• You can customize the additional features using the "Show" drop-down menu and by checking the "Use Small Size" box.