when someone's yelling at you how do you get them to stop?

Just agree with everything they say. Then they'll have nothing to yell about.

you walk away, and  say,  we'll continue the conversation when you can act like an adult. 

If somebody is yelling at you disrespectfully slap the living crap out of them and yell at them tell them you will not disrespect me again or I will whoop your mother effing ***!  Of course if it's an adult and you're a kid your Sol

By leaving so you don’t have to hear it. And then stay away until they’re ready to talk respectfully. Respect is a 2-way street!

Start speaking in a whisper.  It works most of the time because they have to quiet down in order to hear what you're saying.  This is also effective on crying babies and toddlers as well.