Want to add a space to your Mac Dock? Tis Easy!

To add a spacer to the applications (left) side of the Dock, run the following in the terminal:

To see your changes, restart the dock with killall Dock. To add a spacer to the documents (right) side of the Dock, run the following:

Again, killall Dock to see your changes. Once the spacer is in the Dock, you can drag it around to move it. You can even drag it between the application and document sections, if you wish. Run either command multiple times to add multiple separators.

Simples! Enjoy!