In this example, I will create a service to change the wallpaper, then give it a shortcut to change it manually if I feel bored.

Create a service

Open Automator, click File menu, choose New, in the window select Service.

On the top, Service receives to No Input and in Any Application.

In the left pane, click Library > Utilities > Run AppleScript.

Delete all the exiting code, paste following:

tell application "System Events"
set rotinterval to change interval of current desktop
set change interval of current desktop to rotinterval
end tell

Click Run to test if the script can do what we want.

If it works, Then click  file, save, Give it a name (ChangeWallPaper in my case)and click Save.

Bind a shortcut to the service

Go to the Preferences > Keyboard > Shortcuts > services.

Scroll down to the Bottom, under General , find ChangeWallPaper. Click it, then click Add Shortcut button, give it a shortcut.

All Done.