Just quick useful post for separating out your doc items. I’ve had a few coworkers ask how I was able to break the icons in my dock into groups. You can achieve this by entering the following into Terminal.app (or iTerm.app)
defaults write com.apple.dock persistent-apps -array-add '{"tile-type"="spacer-tile";}'
Enter the following for however many breaks you want to add, Dont worry they are easy to remove by dragging off the Dock just like any other icon. You won’t see the changes right away and will need kill the Dock before you’ll see the changes, OS X will detect the Dock is no longer running and automatically relaunch it with the new settings. Now simply drag the spaces wherever you want them.
killall Dock