How to be a screamer?

Ok im tryin 2 scream like the likes of... Corey Taylor, Fred Durst, and of course Chester Bennington. I almost got it but Im tryin 2 get the technique just right. And plus I hear theres a wrong way to bein a screamer and when I scream I just tighten up my throat and scream 2 the best of my ability so I hope dats right and if its not then what is?