Right-click on a folder in a Finder window and select Automator -> newfolder to create a "NewFolder".

open -a Automator

#--------------------------------------------------

Drag or add actions here to build your workflow:
Library: Finder -> Action: Get Selected Finder Items
Library: Automator -> Action: Run Shell Script
                                 - Shell: /bin/sh
                                 - Pass input: as arguments

current_dir="$@"
name_of_new_dir="NewFolder"

if [[ -d "${current_dir}" ]] && [[ -w "${current_dir}" ]]; then
   /bin/mkdir -p "${current_dir}${name_of_new_dir}"
fi

exit 0


# now save the newfolder Automator workflow as a contextual menu item
Automator -> File -> Save As Plug-in ... -> Save Plug-in As: newfolder -> Plug-in for: Finder -> Save

#--------------------------------------------------

open ~/Library/Workflows/Applications/Finder/newfolder.workflow

# now open your Home directory, right-click on a folder and select Automator -> newfolder to create a "NewFolder" 
open ~