K.I.
Terrible Two's are nothing. Wait until she's three!!!
Anyway, the best way to calm a tantrum is to be there for her. Let her know that you are there for what she needs. Keep your voice calm and even whisper. It forces her to quiet down so she can hear you.
Sometimes a hug is all she needs. Don't try to force it though. You might try telling her that you understand that she is frustrated with whatever is making her upset and that you'll help her if she wants it.
But, all you can really do is let her go. If she's out in public or about to hurt herself or others, you'll have to physically remove her, but that's better than being hurt.
I was queen of tantrums when I was little. Good luck,
K.