I’m working on teaching Bentley the “Touch” command.  I like to think of this as a gateway command.  Once you can get your dog to reliably touch on command, you can change what he is touching and gradually change the command to get him to do things like ring a bell or turn on the lights.  In the video I use a sticky note as a target so that Bentley learns that he needs to touch the little piece of paper and not just my hand.