I have always just used a very STERN voice when saying "NO NO!" - I used to also sometimes clap my hands if they weren't listening well while telling them no. I don't have to do the clapping anymore as they now listen with just a "NO NO..." - every once in a while I will have to do the loud clapping with Tatum because she can be a little brat
lol, but for the most part, I don't. I used to also shake my finger at them while saying "NO NO!" in a very stern voice...and I don't know why, but that also seemed to help