One of the cues I use most often if “wait”. This is a great tool for teaching self-control, but it’s also important for safety such as when you are getting out of the car or opening an exterior door. Obviously we still need work in the car, but Wally is a rockstar at the door!
Initially “wait” was hard for Wally since there’s nothing more fun than jumping into the big, exciting world. What, you’re surprised that a terrier would have ants in his pants to get out there and raise hell? I started this by asking him to wait at the front door before we went out. I would say “wait” and reach for the doorknob, then reward him for not moving. This moved up to turning the handle, opening the door an inch, a few inches, etc and now I can open the door entirely and step outside while he waits (I’ve gotta scope it out for renegade squirrels) .
Now I don’t even have to say “wait” at the front or back door (I often do tho), Wally will just look at me until I say “ok”.