Organize your dock using spacers

A simple way to organize the dock in groups of apps is using a white space as shown in the example below.

Open your Terminal app then past and run the following command:

defaults write com.apple.dock persistent-apps -array-add '{"tile-type"="spacer-tile";}'; killall Dock

This will create a spacer at the end of your dock. This space can be dragged around like any other app icon in the dock.

Run the command once for every new desired spacer.