Well the haka , is a war dance .
You have to put alot of power into the moves you do , when you are doing the haka
it is not to be played around with . the haka was a death tool , this dance was used in battles to intimidate their enemy.
You have to show throughout your moves ,that your putting all your strength into it .You have to show that you are strong , very powerful and you have no intention of being nice. Your expressions need to be strong and scary , your arms,legs and whole body needs to be energetic as if you are putting all your energy into every part of your body and releasing it into peoples faces . The energy around you has to be strong , you shall know when your doing the haka properly because people around you should feel intimidated and scared.