Hey y'all!

So basically I've been really getting into electro and that sort of thing. And that made me ponder... what makes a growl?

I have been tinkering here and there and haven't gotten something that sounded like a growl. well technically it is a growl, but its muddy, loud, and doesn't sound remotely good. I was wondering if I could get some tips and basic things I should keep in mind when making growls for fillers. Any feedback is much appreciated.