1. Open a Finder window
2. Click on View on the Finder Menu then click on Customize Toolbar.  (Alternatively, you can right click on the Finder Toolbar, then select Customize Toolbar)
   
   
3. A Finder customization window will drop down from the active Finder window  which states "Drag your favorite items into the toolbar ..." will appear
   
   
   
   
   
   
4. Drag whatever you like to a location you would like the item to appear.  In this example, the Get Info icon will be placed to the right of the view icons:
   
   
5. Click Done when you're finished with your customizations.  In the example demonstrated, the toolbar will appear as follows:
   
   

Other Tips

• 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.