The young ones know one word very well: "RAUS!"
(German command for "Get out!")
Of course, I don't always use it correctly, I will also use it for "get down" because the command is just too long and isn't nearly as effective.
Tone and melody? Yep, those work too.
Treats? Sure, if your cat will eat treats...mine are a little quirky about treats.
Don't take that to mean that I yell at my cats, I don't. Why? They'd think I'm the noisy person spoiling their fun and ignore me. I get further with them actually if I speak directly to them, almost like reasoning with a child.
Keef will chirp and trill and squeak her replies to my request that she please get down and NOT try to get on top of the wine rack on top of the fridge...or please not try to chase that shadow any further up the wall at 3am when she's already at the highest point in the room... Keef pushes limitations.
Sofia is a brat at times and will do things she knows will get my attention whether it is positive or negative and then get this hurt look in her eyes when she doesn't get positive reinforcement for her negative behavior. That being said, Sofia will nearly always come if I call her.