Depending on age, but with both my children, if they're having a doozy, I calmly get down to their level and say firmly " (full name, means business!), DO we throw tantrums in this house?! No, we use our words. If you cannot calm down by the time I count to 3, you can sit in time out until you are ready to talk". Sometimes it will give them something else to focus on because I expect an answer, other times not so much. If we are at home and have a scream fest they go to their room to calm down and we have a chat after about how we feel, why we were angry, and also that anger is ok, but there are ways to deal with it that aren't screaming lol. If out and about and there is no calming down, we go to the car and we will sit there until they've calmed enough to talk. If I think we can go back to what we were doing, I try to, because I gotta get stuff done! But if its a battle because they're tired hungry etc, we pack it in.
Didn't realise it'd be an essay, sorry!