It doesn't have to be any different. I personally don't have a "watch me" command as I play the name game a ton with a puppy and actively train that their name means look at me. However, most people over use their dog's name so much, whenever we pet them we coo their name, so dog's learn to ignore their name pretty quickly. People also tend to repeat their dog's name a lot in commands and this also equals a dog ignoring their name. So you don't have a specific cue like "Watch me" to get your dog's attention, but most people need it. Either way, actively training eye contact is what's important.